Preparations
Capture Rate
Each legendary is assigned 
with a  numerical catch rate, as are all wild  Pokémon. Essentially, the higher  the Catch Rate, the higher the chance  of capture. The Catch Rate is  plugged into a formula, which determines  whether the Pokémon will be  captured or not. While the actual in-game  formula is quite complex,  Community Member X-Act has made a formula that  produces nearly exact  results. Note that you must always round down  should you get a decimal.
(( 1 + ( MaxHP * 3 - CurrentHP * 2 ) * CatchRate * BallRate * Status# ) / ( MaxHP * 3 )) / 256
Top Poké Ball Rates :
Master Ball : 255
Timer Ball (30+ Turns) : 4
Dusk Ball (In darkness) : 3.5 
(is this 4.5? see explanation below)
Net Ball (Against a 
Bug- or 
Water-type) : 3
Repeat Ball (Against previously caught Pokémon) : 3
Ultra Ball : 2
Great Ball : 1.5
A Master Ball catches any wild Pokémon without fail, though it may only   be obtained once through Cyrus, or winning the lottery in Jubilife  City.  Timer Balls begin at 1 and increase every 10 turns, with a cap of  4.  Quick Balls begin at 4 and decrease to 1 after the first turn. 
Neither  of these Balls exceeds the rate of the Dusk Ball (this isn't actually removal, but if this is true, then the dusk ball's rate needs to be higher),  and are somewhat more  circumstantial. All other balls have a catch  rate of 1 against the  legendaries. Dusk or Ultra Balls are 
the preferred 
Balls while Timer Balls can be kept in reserve, keeping some Timer Balls  in reserve.
Status#s :
Freeze : 2
Sleep : 2
Paralysis : 1.5
Burn : 1.5
Poison : 1.5
None : 1
As you can see, sleep is your best bet, due to the lack of reliable  freeze moves. Paralysis is a much lower 
# number, so sleep moves are preferred.  You should never poison 
(removed comma) or burn the legend; this sets a time limit on  the longevity of your legend's lifespan.
The catch 
rate of the legendaries is 3, except for Manaphy, 
who which is  obtained in an Egg, Dialga and Palkia, 
who which are 30, and Shaymin, 
which is  45.
Let's say we try to catch a Level 5 Max HP Magikarp with a Dusk Ball. Magikarp's Catch Rate is 255.
Capture Rate = (( 1 + ( MaxHP × 3 - CurrentHP × 2 ) × CatchRate × BallRate × Status# ) ÷ ( MaxHP × 3 )) ÷ 256
  = (( 1 + ( 18 × 3 - 18 × 2 ) × 255 × 3.5 × 1 ) ÷ ( 18 × 3 )) ÷ 256
  = (( 1 + ( 54 - 36 ) × 255 × 3.5 × 1 ) ÷ ( 54 )) ÷ 256
  = (( 1 + 16065 ) ÷ 54 ) ÷ 256
  = ( 16066 ÷ 54 ) ÷ 256
  = 297 ÷ 256
  = 1.162181712962963
  = 100%
 
  Any decimal numbers were not shown, and 
are simply rounded down.
So, if the end result is over 1, you have a 100% chance to capture the   Pokémon. However, due to varying IVs, it is very difficult to know the   max HP of the legendaries, let alone determine their current HP. The   formula is simply here for reference 
(removed comma) and a little bit of insight into  why certain Balls or 
status effects are used.
Ball Capsules
(i personally got confused with this title and  immediately thought of the actual "ball capsules", the ones that give  the fancy appearances when you send out a pokemon. perhaps you can  change this title? ball preparations? poke balls?)
Just as you wouldn't go into the woods without proper equipment, you   can't expect to catch the legendary Pokémon of Sinnoh without being   prepared. You'll need to stock up on Poké Balls, as explained above;   Dusk Ball is the most effective. These can be picked up at most   late-game PokéMarts, and are available before you fight your first   legendary. You'll want to have at least 50 Dusk Balls on you for each   encounter, and there are 11 legendaries that are obtainable per game   cartridge 
that are caught in Poké Balls (including event Pokémon). That  totals 550 Dusk Balls, and you'll probably want to have at least 50  Ultra and/or Timer Balls in reserve.
(for the red part, it's not really removal. it's  more like idk what you're talking about. if they're already "caught" in  poke balls, then you can't catch them in dusk balls. this wants some  rewording or removal overall.)
Granted, it wouldn't be 
most cost  effective to go out and buy 600 Poké  Balls at once, so it is best to  only carry around 100 Dusk Balls and 50  Timer/Ultra Balls at one time.  This is great if say, Uxie is caught on  the first Dusk Ball thrown,  whereas Azelf takes 65 
Balls. If you  haven't  beaten the Elite Four yet, and you are in the forced battle  with either  Dialga or Palkia, 60 Ultra/Dusk Balls will do fine; they  have the  second highest catch rate for legendaries caught, and Ultra  Balls could  be your primary weapon if you don't want to wait for night.  Shaymin can  also be caught with Ultra Balls if 
needed be.  Timer Balls are a viable  option if you are not battling in a cave, and  if you wait long enough,  which you typically shouldn't have to. Palkia  has the added advantage of  being easy to catch with Net Balls if you 
so choose 
so.  For the  legendaries, bar Dialga/Palkia and the roamers Mesprit,  Cresselia,  Articuno, Zapdos, and Moltres, as well as the ones obtained  in events,  you can use Dusk Balls without worry; they are all  conveniently located  in caves, which boost the Dusk Ball's  effectiveness. For the other  legendaries, you'll have to wait until  between 20:00 and 4:00 on your DS  clock for the Dusk Balls to work to  their full potential. Or, you could  always clone a whole bunch of  Master Balls via the Pokémon Emerald  Battle Tower cloning glitch and  transfer them to your Platinum game via  Pal Park. 
The Synchronizer
After you get yourself some Balls, you'll want to get a Synchronizer.   “What's a Synchronizer?” you may ask. Well, when you have a Pokémon with   the ability Synchronize in the first slot of your party, all wild   Pokémon have a 50% chance of inheriting the nature of that Pokémon. An   even better trait is that the Pokémon doesn't have to be alive for   Synchronize to work its magic, so you can have a fainted Synchronizer at   the start of your party, and the effects remain intact. This way, you   can have an increased chance of getting the nature you want, which is   something you'll have to decide on your own; which nature to use is up   to personal preference. Refer to the analyses in the SmogonDex for ideas   if you're stuck.
Now, where will you find these Pokémon that Synchronize? Well, the list of all 
the Pokémon that can have this trait is as follows:
Abra, Kadabra, Alakazam, Mew, Natu, Xatu, Espeon, Umbreon, Ralts, Kirlia, and Gardevoir
Pre-National Dex, you have access to Abra, Kadabra, Alakazam, Ralts,   Kirlia, Gardevoir, Umbreon, and Espeon as Synchronizers without trading.   Abra and Kadabra can be found on Routes 203 (Abra only) and 215, Eevee   is given to you by Bebe in Hearthome City, and Ralts can be caught on   Route 208 and Route 209, but keep in mind, they might not have the   nature you want or the Synchronize ability, except for Umbreon, Espeon,   and Mew, 
who which  have Synchronize as their only ability. It's a pain for  this little  pre-National Dex portion of time; so the best you can do is  probably  convince someone to trade with you, or breed/catch one of these  Pokémon  with the desired nature(s). 
After the National PokéDex (which is the best time to capture the  legendaries, including Giratina if you didn't capture 
it  in the Distortion  World), it is considerably easier to get  Synchronizers. You can soft  reset at the Game Corner Prize Shop in  FireRed/LeafGreen for Abra, or  transfer over Synchronizers you had in  the previous generation for  catching Ditto in Emerald.
The Catcher
Get your Synchronizer, and if you are planning on transferring over   unlimited Master Balls from your previous generation games, feel free to   read the little blurb about Manaphy and be on your way to the next   section. If not, you'll probably need a good capturing Pokémon. What   makes a good capturing Pokémon? A Pokémon that can learn both a reliable   sleep move (60 Accuracy and up) and False Swipe (a TM found in the   Veilstone Department Store that keeps the wild Pokémon at 1 HP if it   would have fainted). True, Dialga, Heatran, and Giratina 
in particular  all laugh at the thought of 
the move False Swipe,  and the rest of the legendaries  aren't going to be crippled by it, but  it's still great to get the HP of  the legends' as low as possible  before throwing your 
Balls. A list of  Pokémon that meet the above criteria is as follows:
 Parasect, Mew, Smeargle, Breloom, and Gallade
   
  Gallade is probably the easiest to obtain, as you can catch Ralts   early in the game and obtain a Dawn Stone prior to facing Giratina.   Gallade learns Hypnosis as a Ralts or Kirlia, and can be taught False   Swipe via TM when it has fully evolved into a Gallade. Furthermore,   Gallade learns Mean Look as an egg move, so it can be used to trap the   roamers when you encounter them. Parasect can only be obtained post   National Dex and is a good alternative for Gallade, but you must get it   up to a very high level, with an Attack-boosting nature. If you do end   up using Parasect, make sure you obtain it 
in a fourth generation game, so  it has the ability Dry Skin, rather than Effect Spore, which could give  
the a  legendary an undesired status ailment. Breloom is a good option as   well, learning Spore, the most accurate sleep move available. However,   you must breed False Swipe onto it as an egg move, and, like Parasect,   avoid the ability Effect Spore. While Smeargle has access to Spore and a   STAB- and potentially Technician-boosted False Swipe, its stats are   poor, and it must Sketch the aforementioned moves from other Pokémon.   Finally, Mew only learns Hypnosis via Pokémon XD and My Pokémon Ranch 
(but is it a good option?).   In conclusion, Gallade is probably the best catcher out of the   aforementioned Pokémon; it's just a bit of a pain to get Ralts/Kirlia 
a  high level to get high enough to learn Hypnosis. 
Keep in mind that (removed comma) your catcher should be of a high level  anyway
; (semi-colon) hopefully aiming for level 80+ is a solid level 
to aim for limit,  as level 80 is  the highest level of a legendary you may encounter. If  you do not want  to spend too much time leveling up your catcher, then  just level up  until it can outspeed the legendary you are going to  capture. If you're  aiming to catch Giratina, Azelf, Uxie, or Mesprit  pre-National Dex, then  it would be wise to capture a Ralts, as  Kirlia/Gallade is a good  Pokémon in-game anyway and Gallade is the only  one that can learn  Hypnosis and False Swipe, without trading with  another game, prior to  receiving the National Dex. However, False Swipe  won't affect Giratina  without the use of moves 
like such as  Foresight or Odor Sleuth, but even if you  can't use Gallade's False  Swipe to harm Giratina, you can use its  Hypnosis to inflict Giratina  with sleep and improve your odds of a  successful capture.
  
The "One Under" Pokémon
An optional Pokémon that you may wish to take with you is the "one   under" Pokémon. This is a Pokémon that has a Speed stat one point below   the maximum of the legendary you're trying to catch. This is for the   Pokémon you really need to have reach a certain 
Speed. It isn't the  wisest choice to bring one of these along for every legendary
, (comma)  however;  the "one under" Pokémon can be a pain to get, but it will be  worth it if  you don't have Master Balls. The idea is to switch your  Synchronizer to  the "one under", then have the latter use an attack. If  the legendary  goes first, switch to the capture Pokémon and continue  the battle. If  not, reset. This "one under" should either be of a high  level or be  holding a Focus Sash (which can be obtained from the man in  the house  west of the Pal Park the third time you show him a Pokémon).
If you are going for a defensive legendary 
who that  is not concerned about  outspeeding certain threats, then you may wish  to go for a different  variation of the "one under" Pokémon that uses  Endeavor. Endeavor is a  move that takes the foe's Pokémon's HP down to  the HP the Endeavor user  currently has, but fails if the Pokémon using  Endeavor has more HP than  its target. This can be abused by giving your  Endeavor Pokémon 1 less HP  than the maximum HP of the legendary you  are going for. If your "one  under" Pokémon's Endeavor attack fails,  then you know that the legendary  you are fighting does not have the  amount of HP you are looking for, so  you can reset without having to  capture it. If Endeavor reduces the  legendary's HP, then you know it is  fine to resume trying to capture it.  However, this Pokémon must also  be faster than the legendary, so it  does not risk taking damage, which  would result in 
a false 
positive information.  Unfortunately, Endeavor is a Normal-type move, which renders it  ineffectual against Giratina, 
who which is one of the Pokémon that could  benefit from this strategy.
Other Items and Pokémon
Take another stop at a PokéMart; you'll want to buy a few Revives and   Hyper Potions/Max/Full Restores if you're far enough in the game.   Revives are also found in the Underground fairly easily, along with   their more powerful variant, Max Revives. These are mainly for keeping   your main capture Pokémon alive, as well as the remainder of your party.   About 30 Super Repels are almost mandatory too (these are actually  more  cost effective than Max Repels). 
5 Five or 
so more Escape Ropes are 
also great 
to have (and  almost necessary for after Heatran). You should always bring a team of 
3 three  high-leveled Pokémon (the other two are HM slaves, but leveling them up  is 
great helpful)  with your Synchronizer in the lead. The only exceptions are  when you  are catching any of the runners. In this case, you could use  Wobbuffet  in your first slot in order to trap them, or use Mean Look  Gallade  (this is recommended, as Gallade is an excellent catcher).
If you are going to capture Regigigas, you will need to bring along   Regirock, Regice, and Registeel; otherwise, you cannot initiate a battle   with it. With Manaphy, you will need two Nintendo DS or DS Lite (or a   combination of the two) systems, one with a copy of your game, and one   with a completed Pokémon Ranger game (includes: Pokémon Ranger, Pokémon   Ranger: Shadows of Almia, and Pokémon Ranger: Guardian Signs) that has   not yet given out a Manaphy. If you don't own two systems, try  borrowing  one from a friend, as the actual act of transferring Manaphy  doesn't  take too long. Just be sure to beat the Pokémon Ranger game in  advance.  You will also need a random Pokémon, preferably with a  different nature  to the one you desire for Manaphy, and two boxes with  empty spaces.
Tricks of the Trade
So, before you go after even your first legendary (Giratina)
, (comma) keep in mind a couple tips:
Always save before the legendary. For Arceus, you must save before you reach the top of the stairs.
Check the stats in the legendary's section before you save, and after  you compare the stats and 
are feel  interested, check them with Metalkid's IV  Calculator. You can use some  Rare Candies and record the stats for each  level if you wish, but for  legendaries this is generally not necessary  due to the high base stats.  
  
Learn about characteristics; they can usually help you determine the   exact IV of at least one stat when combined with an IV calculator and   the stat list. 
   
  Once you have gained access to the Battle Frontier, it is also   possible to use the IV Reporter in the Battle Tower to help determine   your Pokémon's highest IV. 
However, given Due to the existence of  characteristics, this is 
most more useful when your Pokémon has the same  numerical value for more than one IV.
To instantly check the Hidden Power of your legendary, consult the   Hidden Power Reporter in Veilstone City's Game Corner Prize Exchange.   This allows you to check if your Pokémon has a desirable Hidden Power   type, if it needs one, and 
otherwise help narrow down the range of  possible IVs when using a calculator.
 
Make sure you have a maximum of five Pokémon in your party whenever you   are about to fight a legendary. This allows you to check the nature and   stats of your legendary while it is in your party, saving you a trip   back to a Pokémon Center to check Bebe's PC.
If you don't like the Pokémon, press L + R + Start + Select   simultaneously. This process is known as soft resetting. It is less   stressful on your system than turning the power off and on again, and it   saves time for you as well.
Keep realistic expectations. If you're only willing to accept a   legendary with quadruple 31 IVs, you could be there for a very long   time. It is much harder to get a legendary Pokémon with great IVs 
than compared to a 
 bred Pokemon.  However, you can remedy this problem by RNG abusing your  legendary,  which allows you to control its nature and IVs to an extent.   Information on PRNG manipulation can 
be found 
here.
   
Watch the HP bars if you're not using Master Balls. Compare the   approximate damage done by your Pokémon to the HP of the legendary once   you've caught it, and vice versa, with the legendary's Attack/Special   Attack. This should help you out; if you do too much damage to a   defensive legendary, you can reset without the 
battle processing. The  same goes for if an offensive one doesn't do enough damage to 
your Pokemon.
Future Sight, an attack used by quite a few Platinum legendaries, has   damage determined by the Special Defense of the Pokémon that is   targeted. So if Azelf uses Future Sight against a level 1 Bidoof, and   you switch to a level 100 Blissey, 
you'll your Blissey will still take massive damage when  the attack hits.
If a legendary runs out of Power Points for all 
of  its moves, it will use  the move Struggle. Struggle is a typeless  attack that causes recoil  equal to 25% of the user's maximum HP. So  once a legendary starts to  Struggle, it isn't 
long remaining for in this world 
for long, especially if 
your Pokemon has  previously used False Swipe to lower it to 1 HP.
Catching the Legendaries
Now that you have some more knowledge, or at least something to  reference 
to,  get out a piece of paper and a pencil. Be prepared to make a  little  tick mark every time a legendary uses a move, and put two ticks  if your  Pokémon has the ability Pressure. This will be used to reference  the  amount of PP the legendaries have before Struggling, which is  listed in  this section. Note that if your sleep-inducing Pokémon is  faster than  the legendary, 
it the legendary (didn't know what "it" was) will use a PP (or two with Pressure) the  turn it is put to sleep, and of course it still uses PP the turn it  wakes 
up. PP is not used up while the legendary is asleep.
So, in which order should you catch the legendaries? Giratina is the  first 
one that  you can capture of course, but after you have obtained the  National  PokéDex it's a matter of personal preference. It's logical to  go for  the lower-leveled legendaries first, and work your way up. 
Doing Catching   the five roamers (Mesprit, Cresselia, Articuno, Zapdos, and Moltres)   consecutively is probably going to be stressful, and is not recommended.   So let's get started!
(backspace this)
Giratina (Origin and Altered Forme)
Giratina is first encountered in its Origin Forme as part of the   storyline at the end of the Distortion World, after Cyrus has been   defeated. Since this occurs before you receive the National Dex, you may   not have the appropriate Pokémon to efficiently catch Giratina, so   expect a challenge if you attempt to capture it at this point. However,   if you KO it or flee from it, Giratina will re-appear at the end of   Turnback Cave after you beat the Elite Four. Turnback Cave is located at   the end of Spring Path on Route 214. Bring Pokémon with Defog and Rock   Climb if you're going to catch Giratina at Turnback Cave, along with   some Super Repels, as you may be wandering through the various rooms of   Turnback Cave for a while before you reach Giratina. You must reach   Giratina within 30 rooms, and despite the cave's name, do not turn back   or you will wind up at the beginning of the cave. Giratina is in its   Altered Forme when you encounter it in Turnback Cave. Since Giratina is a   Ghost-type, False Swipe will not normally affect it, so bring a  Pokémon  with the move Foresight or Odor Sleuth, so that you may hit  Giratina  with Normal-type moves (notably, Endeavor and False Swipe).  Giratina is  at level 47 on both occasions in the Distortion World or  Turnback Cave,  just like the dragons in Diamond and Pearl.
Giratina's Maximum Stats (Origin Forme)
Stat Max- Max Max+
HP - 212 -
Atk 118 132 145
Def 101 113 124
SpA 118 132 145
SpD 101 113 124
Spe 93 104 114
 
(backspace this)
  Giratina's Minimum Speed (Origin Forme)
   
  Min- Min Min+
  80 89 97
Giratina's Maximum Stats (Altered Forme)
Stat Max- Max Max+
HP - 212 -
Atk 101 113 124
Def 118 132 145
SpA 101 113 124
SpD 118 132 145
Spe 93 104 114
   
  Giratina's Minimum Speed (Altered Forme)
   
  Min- Min Min+
  80 89 97
Giratina's Moveset (Origin and Altered Forme)
Ominous Wind (5 PP)
AncientPower (5 PP)
Dragon Claw (15 PP)
Shadow Force (5 PP)
 
  Total PP = 30
That's right, only 30 PP, so try and make this a quick capture. However,   since Shadow Force is a two-turn Attack, you have 35 turns until   Giratina starts to Struggle. Shadow Force can do a lot of damage, but   you can switch to a Normal-type to negate it. Both Ominous Wind and   AncientPower can raise all of Giratina's stats, making it 
even more difficult 
to  capture. 
   
  Whether you're catching Giratina in the Distortion World or Turnback   Cave, Dusk Ball is the best option as it has a Ball Rate of 4 in both   locations, and with Giratina's catch rate set at 3, you're going to need   every advantage. After you have captured Giratina, in either location,  a  portal to the Distortion World will appear in its room in Turnback   Cave. Enter the portal to obtain the Griseous Orb, which will raise the   power of its Ghost- and Dragon-type moves and keep it in its Origin   Forme outside of the Distortion World. 
   
Uxie
Uxie is found in Acuity Cavern, which is in the middle of Lake Acuity.   This is the lake just west of Snowpoint City. Simply spray a few Super   Repels as you're on your way, and Surf onto the little rocky island that   houses a cave. Inside is the defensive one of the Psychic trio, Uxie.   You can walk/ride right up to Uxie without it attacking you, so go  ahead  and go into the space in front of it to save. Uxie is fought at  level  50.
Uxie's Maximum Stats
Stat Max- Max Max+
HP - 150 -
Atk 85 95 104
Def 135 150 165
SpA 85 95 104
SpD 135 150 165
Spe 103 115 126
Uxie's Moveset
Swift (20 PP)
Yawn (10 PP)
Future Sight (15 PP)
Amnesia (20 PP)
 
  Total PP = 65
Yawn can be a bother, but if you switch your Pokémon out, 
its effects will be negated will negate  its effects. Before you leave Lake Acuity for good, check the land in  the northeastern corner for 
a Poké Ball containing a TM14 Blizzard.
Azelf
Azelf is found in Valor Cavern, in the middle of Lake Valor. In case   you're too lazy to check the town map, this is the lake just southwest   of Veilstone City. Simply spray a few Super Repels as you're on your   way, and Surf onto the little rocky island that houses a cave. The   offensive one of the trio, Azelf
, (comma)  resides here. You can walk/ride right  up to Azelf without it attacking  you, so go ahead and go into the space  in front of it to save. Azelf  is fought at level 50.
Azelf's Maximum Stats
Stat Max- Max Max+
HP - 150 -
Atk 130 145 159
Def 81 90 99
SpA 130 145 159
SpD 81 90 99
Spe 121 135 148
Azelf's Moveset
Swift (20 PP)
Uproar (10 PP)
Future Sight (15 PP)
Nasty Plot (20 PP)
 
 
(backspace this)
  Total PP = 65
Uproar prevents 
sleep status for 2 to 5 turns, though luckily it's only 1  PP for that amount of time (2 under Pressure)
. (period) Beware that and with Nasty Plot it Azelf's Uproar  can rip through your team 
with Nasty Plot if 
it's your Pokémon are under leveled. Before  you depart from Lake Valor, check the land in the southeastern corner  for 
a Poké Ball containing a TM38 Fire Blast.
Mesprit
Unlike most legendaries, Synchronize will not work on Mesprit. It is   hiding at Lake Verity, but it won't stay there for long. Be sure 
to  check  the land in the southwestern corner for a TM25 Thunder, and set  the  Pokétch Map Application as your current App. This is obtained from  the  Pokétch Creator in Jubilife City, after you have won 
3  three   Gym Badges. Go to  Twinleaf Town, using a Super Repel as you're on  your way, and Surf onto  the little rocky island that houses a cave.  Inside is the balanced one  of the trio, Mesprit. You can walk/ride  right up to Mesprit without it  attacking you, so go ahead and go into  the space in front of it to save.  Mesprit's nature and IVs are set when  you talk to it. However, it will  run off, and you'll have to go  through a dialogue with Professor Rowan  every time it does. If you're  not using Master Balls, be sure that it is  between 20:00 and 4:00, so  that you can use Dusk Balls at their full  potential. 
Mesprit will jump to a random route on the map. It cannot appear at   lakes, in cities, or in caves, but everywhere else is fair game. If you   Fly somewhere, Mesprit appears to jump to a random route, but if you   move onto a different route (or in longer routes, a different section of   the same route) Mesprit will move to an adjacent route. If it tries to   move through a city, cave, or any of the lakes, it may jump to a  random  location as well, so instead of chasing it all across Sinnoh,  Fly to  Jubilife city.
Now, get on your Bike and switch to the faster gear, if you aren't on it   already. Watch Mesprit's location on the Pokétch (it's marked by a   small Pikachu head) and go back into Jubilife from an adjacent route.   What you are doing is making Mesprit change location. Eventually, it   will either appear in your route, or in a route around Jubilife.   Remember that moving to the adjacent route will force Mesprit to switch,   so if you're in Jubilife and it's on the route to the left, try  heading  into one of the other routes and hope it ends up there. A word  of  precaution: the route just above Jubilife has a cave in the middle,  and  the two sections of plain land are separate locations. If Mesprit  is in  the part of the route directly linked to Jubilife, it will appear  right  above the city, without a space. If your lead Pokémon is level  50 or  below, spray a Super Repel to keep other wild Pokémon away. If  your lead  is over level 50, do not use any Repels, as that would  prevent Mesprit  from showing up. Luckily, Mesprit has a high chance of  showing up in any  area it is in. Mesprit is fought at level 50.
Mesprit's Maximum Stats
Stat Max- Max Max+
HP - 155 -
Atk 112 125 137
Def 112 125 137
SpA 112 125 137
SpD 112 125 137
Spe 90 100 110
Mesprit's Moveset
Swift (20 PP)
Lucky Chant (30 PP)
Future Sight (15 PP)
Charm (20 PP)
 
  Total PP = 85
Be sure to trap Mesprit right away; it will attempt to flee the very  first turn of battle. Any status effects and damage done 
on it will be 
on it transferred   when you find it again. However, if you do not want to keep throwing   hopeful Poké Balls at Mesprit, use a faster Pokémon with the ability to   use trapping moves, such as Mean Look, and then Baton Pass to your   Catcher. From Mesprit's moveset, Charm would be the most annoying move,   as it will weaken your Pokemon's physical attacks. Therefore, you may   have to spend a few more turns reducing its HP with False Swipe. 
Heatran
Heatran is located inside a cave at the end of the inner chamber of   Stark Mountain. When you first visit Stark Mountain and attempt to enter   the mountain itself, you will have to play through an event involving   Team Galactic where you team up with another trainer named Buck. Once   you have completed that side quest, return to the Survival Area and   follow Buck into a house. When you enter, you will meet and speak with   his grandfather. 
Afterward, you may  return to Stark Mountain and catch  Heatran. It is important that you  return to the Survival Area and speak  with Buck's grandfather;  otherwise, Heatran will not appear.  Remember  to bring Pokémon with  Rock Smash and Strength 
at least to get  to  Heatran's cave. Rock Climb is optional, but it will help you get to  the  cave faster. Heatran is encountered at level 50. 
Heatran's Maximum Stats
Stat Max- Max Max+
HP - 166 -
Atk 99 110 121
Def 113 126 138
SpA 135 150 165
SpD 113 126 138
Spe 87 97 106
Heatran's Moveset
Metal Sound (40 PP)
Crunch (15 PP)
Scary Face (10 PP)
Lava Plume (15 PP)
 
 
(backspace this)
  Total PP = 70 PP
Heatran's secondary 
Steel typing will draw the battle out if you're  relying on False Swipe to reduce its HP. Luckily, with 70 PP between 
its  four moves, you can spare a few turns to chip away at its HP. Scary Face  will reduce your 
Pokemon's  Speed and give Heatran a chance to waste one more PP  before your  Pokémon can make a move. Metal Sound's 2 stage SpD drop lets  Heatran  inflict more damage with Lava Plume. Furthermore, Lava Plume  has a  scorching 30% chance of burning your Pokémon, so be sure to bring  some  Full Heals just in case. 
Regigigas
Regigigas is located on the basement floor of Snow Point Temple. HM   moves are not necessary to reach Regigigas, but each floor has its own   ice puzzle you must solve. Before you make your journey down the   Snowpoint Temple, remember to bring Regirock, Regice, and Registeel   along, as you will need them to actually engage Regigigas in battle for a   chance to capture it. Regigigas is at level 1 when you battle it. 
  
Regigigas's Maximum Stats
Stat Max- Max Max+
HP - 13 -
Atk 7 8 8
Def 6 7 7
SpA 5 6 6
SpD 6 7 7
Spe 6 7 7
Regigigas's Moveset
Confuse Ray (10 PP)
Foresight (40 PP)
Knock Off (20 PP)
Dizzy Punch (10 PP)
Total PP =70
Yes, you read correctly; the king of the Regis is now found at level 1.   Simply inflict Regigigas with a status condition (preferably sleep),  use  False Swipe to instantly bring it to 1 HP, and start tossing your   choice of Poké Ball at it. Since Regigigas is at level 1, Nest Balls   would be an excellent Ball to use on it, since the Nest Ball's Ball Rate   equals the Dusk Ball's Ball Rate when used on a Pokémon at level 1.   However, Regigigas still has a CatchRate of 3, so it may take 
a multiple  tries to catch it, just like any other legendary. 
Dialga/Palkia
 
(backspace this)
 
  Making a return after their debut in Diamond and Pearl, Dialga and   Palkia can be caught at Spear Pillar on the peak of Mt. Coronet.    However, there are a few tasks you must perform before they appear on   Mt. Coronet. Firstly, obtain the Adamant and Lustrous Orbs hidden in a   cave atop the waterfall on Mt. Coronet. Secondly, after you have   defeated the Elite Four and finished the main storyline, go show them to   Cynthia's grandmother. Finally, after speaking with her, go to the   ruins in Celestic Town and press A when you are in front of the painting   inside; Cynthia will appear and talk about Dialga, Palkia, and   Giratina. Once you have completed the previous tasks, 
scale climb Mt. Coronet  and you will find a blue portal
. (period) Press  A while in front of the portal to  battle Dialga. After you have  captured Dialga, leave Spear Pillar. When  you return, there will be a  pink portal
. (period) Press A while in front of it  to battle Palkia. Dialga and Palkia are at level 70 when you encounter  them. 
  
Dialga's Maximum Stats
Stat Max- Max Max+
HP - 241 -
Atk 174 194 213
Def 174 194 213
SpA 212 236 259
SpD 149 166 182
Spe 136 152 167
 
  Dialga's Minimum Speed
   
  Min- Min Min+
  117 131 144
Dialga's Moveset
Roar Of Time (5 PP)
Heal Block (15 PP)
Earth Power (10 PP)
Slash (20 PP)
 
  Total PP = 40
 
  Besides higher stats due to the increase in level, another change from   Diamond is the addition of Heal Block, which replaces one of Dialga's   three offensive moves. This means that unlike in Diamond, you will not   be bombarded with attacks every turn, and have a chance to heal your   Pokémon after Roar Of Time. However, while Heal Block is in effect, only   items will restore your Pokémon's HP. Dialga's Steel-typing grants it 
 resistances to  many attacks (including False Swipe), so it may be worth your  while to  bring a high level Pokémon that can take heavy hits and weaken  it with  Ground or Fighting moves to make False Swiping its HP down to 1   easier; Gallade is a good choice.  
Palkia's Maximum Stats
Stat Max- Max Max+
HP - 227 -
Atk 174 194 213
Def 149 166 182
SpA 212 236 259
SpD 174 194 213
Spe 149 166 182
   
  Palkia's Minimum Speed
   
  Min- Min Min+
  130 145 159
  
Palkia's Moveset
Spacial Rend (5 PP)
Heal Block (15 PP)
Earth Power (10 PP)
Slash (20 PP)
 
  Total PP = 40
Along with the increase in level, Palkia gained Heal Block, so unlike in   Pearl you have a damage-free turn to heal your Pokémon with an item 
of  course. A turn you may need 
could be wasted if  Palkia manages to land a critical hit on  your Pokémon with Spacial  Rend, which is likely due to its high critical  hit ratio. Slash shares  the same increase in critical hit 
ratio, but it  is not as threatening due to  
a the lack of STAB and lower Base Power.  Generally, Palkia should be an easier capture than Dialga. 
Cresselia
Cresselia, like Mesprit and the Kanto birds, roams Sinnoh after 
you  interact with it on Fullmoon Island. To reach Fullmoon Island
, (comma)  travel to  Canalave City, enter the house in front of the boat and  sailor that  take you to Iron Island, press A when your character is  directly in  front of the sailor's son in the bed to learn that he is  having  nightmares, exit the house, and speak to the sailor 
and so that  he will ask you  to go to Fullmoon Island to retrieve the Lunar Wing to  help his son.  When you arrive on Fullmoon Island, you will find  Cresselia in a  clearing. Walk up to 
her it, press A, and 
she it  will flee and become  available for capture in the wild. Remember, you  must save prior to  interacting with Cresselia if you wish to soft reset  or RNG abuse 
her it.   Pick up the Lunar Wing and return to Canalave City. Use the method to   encounter Mesprit to locate and engage Cresselia in battle. Cresselia  is  at level 50 when you encounter it. 
Cresselia's Maximum Stats
Stat Max- Max Max+
HP - 195 -
Atk 81 90 99
Def 126 140 154
SpA 85 95 104
SpD 135 150 165
Spe 94 105 115
   
  Cresselia's Minimum Speed
 
  Min- Min Min+
  81 90 99
Cresselia's Moveset
Mist (30 PP)
Aurora Beam (20 PP)
Future Sight (15 PP)
Slash (20 PP)
Total PP = 85
Like Mesprit, you are best off trying to trap Cresselia 
straight right  away,  as it will attempt to flee on the first turn of battle. Any  status and  damage sustained by Cresselia will remain after you battle  it. An easy  way to catch Cresselia is to use a faster Pokémon with Mean  Look, and  Baton Pass to your catcher or use Gallade
, (comma) who which  can trap it with Mean Look  and weaken it with False Swipe. Overall,  Cresselia's moveset should not  give you any serious issues while you  are attempting to catch it. 
Articuno/Zapdos/Moltres
In the same vein as Cresselia and Mespirit, 
the  Articuno, Zapdos, and  Moltres roam Sinnoh after you obtain the  National Dex. To release the  birds, you must visit Professor Oak at his  house in Eterna City (located  in front of the Cycling Road) and speak  to him. He will only appear in  the house once you have obtained the  National Dex and visited Pal Park.  All three birds are released at  once, and their natures and IVs are  decided at the moment they are  released. Therefore, it will be difficult  to obtain all three birds  with a desired nature/IV combination through 
soft resetting and even RNG abuse  either RNG abuse or soft resetting. 
(sounded a bit plain)   As with the other roamers,  Synchronizers will not work on Articuno,  Zapdos, and Moltres. Luckily,  you can re-release the Kanto bird trio by  KOing the bird you want to  re-release, defeating Elite Four, and  speaking to Professor Oak in  Eterna City again. The bird(s) that is  (are) re-released will most  likely have a different nature/IV  combination. The same method used to  encounter Mesprit/Cresselia can be  used to encounter any of the birds.  However, you cannot tell which  bird you will encounter by looking at the  Pokétch, as they all have the  same marker. Articuno, Zapdos, and  Moltres are at level 60 when you  battle them.  
  
Articuno's Maximum Stats
Stat Max- Max Max+
HP - 196 -
Atk 112 125 137
Def 128 143 157
SpA 123 137 150
SpD 155 173 190
Spe 112 125 137
Articuno's Moveset
Agility (30 PP)
Ice Beam (10 PP)
Reflect (20 PP)
Roost (10 PP)
 
(backspace this)
 
  Total PP = 70
Articuno has a lot of PP, so you will have plenty of turns to catch it.   Look out for Roost, as it replenishes half of Articuno's health, making   all that hard work put into reducing its HP go to waste. Agility will   let it outspeed your Pokémon and waste an additional PP before you can   make a move.  Reflect will reduce the amount of damage done by physical   attacks, namely False Swipe, and when coupled with Roost, it can make   Articuno difficult to capture. 
Zapdos's Maximum Stats
Stat Max- Max Max+
HP - 196 -
Atk 117 131 144
Def 112 125 137
SpA 155 173 190
SpD 117 131 144
Spe 128 143 157
Zapdos's Moveset
Charge (20 PP)
Agility (30 PP)
Discharge (15 PP)
Roost (10 PP)
 
  Total PP = 75
Roost and Agility can be annoying, letting Zapdos restore half its HP  and waste an additional PP by 
outspeeding your Pokémon, respectively.  Discharge‘s 30% chance of paralysis 
is an issue, as a Pokémon inflicted  with paralysis will be slower than Zapdos and 
while fully paralyzed
 from time to time, giving   it a free turn.  However, you can get around Discharge and ensure that   Zapdos cannot damage your Pokémon by trapping Zapdos, then Baton  Passing  to a Ground-type Pokémon. Baton Passing does come at a price
: (colon)  you can  no longer put Zapdos to sleep as no Ground-type, except for a  purified  Marowak from Pokémon XD: Gale of Darkness, learns a  sleep-inducing move.  Inflicting Zapdos with a permanent status  condition
, (comma) such as paralysis,  before Baton Passing is recommended to improve your odds of capturing  it. 
  
Moltres's Maximum Stats
Stat Max- Max Max+
HP - 196 -
Atk 128 143 157
Def 117 131 144
SpA 155 173 190
SpD 112 125 137
Spe 117 131 144
Moltres's Moveset
Flamethrower (15 PP)
Safeguard (25 PP)
Air Slash (20 PP)
Roost (10 PP)
 
  Total PP = 70
Air Slash is the deadliest move in Moltres's moveset, as it hits 
2 two out  of the seven recommended “Catchers” for 4x damage and Gallade for 2x  damage. Additionally, it has a 30% flinch rate
; (semi-colon) however, that 
is  only a  concern if it outspeeds your Pokémon. Safeguard prevents  Moltres from  being inflicted with a status condition, so while it is in  effect, you  can't rely on sleep to improve your odds of a successful  capture. Like  the other two Kanto birds, Moltres has access to Roost to  heal itself,  so you may have to repeatedly reduce its HP. 
Event Pokémon
 
  Regirock/Regice/Registeel
  
Introduced in the third  generation, the Regi trio (Regirock, Regice, and Registeel)
, introduced in the third  generation,  can be obtained in Platinum through the use of an event  Regigigas. The  list of event Regigigas that unlock the Regis in Platinum  include the  following OTs: TRU, テンイむら, EUETE09, EUSMR09, ESTEU09, and  EUVER09. Each  Regigigas has the ID: 07189 (except for TRU Regigigas  whose ID is  03089 and テンイむら with an ID of 07198), is at level 100, comes  in a  Cherish Ball, and has the moveset: Iron Head, Rock Slide, Icy  Wind, and  Crush Grip. The event Regigigas are not region locked, so you  can use  any of these Regigigas, regardless of the language of your game.  The  event Regigigas must be in your party when you are going to capture  one  of the Regis; otherwise, they will not appear.
(avoiding repetition from "the".)
  
Regirock
Regirock is found in Rock Peak Ruins, a cave on Route 228 near the gate   to Route 226. Specifically, the cave is located in front of a rock at   the foot of a sandy slope. Remember 
(removed comma) to bring the event Regigigas in  your party, or the cave will be empty. Regirock is at level 30 when you  battle it. 
  
Regirock's Maximum Stats
Stat Max- Max Max+
HP - 97 -
Atk 66 74 81
Def 120 134 147 
SpA 39 44 48
SpD 66 74 81
Spe 39 44 48
Regirock's Moveset
Stomp (20 PP)
Rock Throw (15 PP)
Curse (10 PP)
Superpower (5 PP)
Total PP = 50
Phenomenal Defense and 
Rock typing (removed comma)  make it difficult to harm Regirock  with physical attacks, so do not  expect a quick capture if you are using  False Swipe to chip away at  Regirock's HP. Curse fortifies Regirock's  already impressive Attack and  Defense, making it harder to weaken and  its attacks more painful.  Superpower has the highest 
Base Power out of  Regirock's attacks; however, it reduces Regirock’s Attack and Defense to  negate some of the boosts it gains from Curse. 
 
  If you visit the cave on Route 228 without an event Regigigas, you will find a Hard Stone at the center of the cave. 
  
Regice
As long as you have an event Regigigas in your party, Regice will battle   you in Iceberg Ruins, a cave near the Route 216 exit of Mt. Coronet.   Regice is at level 30 when you encounter it. 
  
Regice's Maximum Stats
Stat Max- Max Max+
HP - 97 -
Atk 39 44 48
Def 66 74 81
SpA 66 74 81
SpD 120 134 147 
Spe 39 44 48
Regice's Moveset
Stomp (20 PP)
Icy Wind (15 PP)
Curse (10 PP)
Superpower (5 PP)
Total PP = 50
Icy Wind and Stomp are rather annoying. Icy Wind lowers your Pokémon's   Speed every time it hits, and after a few hits, Regice may 
even outspeed your  Pokémon. Stomp may cause 
your Pokemon to flinch, but only if Regice is faster  than 
your Pokémon it. Unfortunately, Icy Wind may give it that opportunity.  Curse raises 
Regice's good Defense and mediocre Attack, but 
it isn't as  threatening as it is on Regirock. Furthermore, it lowers 
Regice's Speed,  which helps your Pokémon by keeping Regice slower than it.  
   
  If you visit the cave in Mt. Coronet near the Route 216 exit without  an event Regigigas, you will find a 
NeverMeltIce at the center of the  cave. 
  
Registeel
Registeel 
is found in Iron Ruins, a  cave on Iron Island. Specifically, the  cave is located at the end of  Iron Island by taking the lift on the  basement floor that has all the  trainers standing facing each other
; (semi-colon) it 
is   also where you helped Riley stop Team Galactic. Like the other Regis,   remember to bring an event Regigigas, or Registeel will not appear in   the cave.
Registeel's Maximum Stats
Stat Max- Max Max+
HP - 97 -
Atk 53 59 64
Def 93 104 114
SpA 53 59 64
SpD 93 104 114
Spe 39 44 48
Registeel's Moveset
Stomp (20 PP)
Metal Claw (35 PP)
Curse (10 PP)
Superpower (5 PP)
Total PP = 70
Registeel is the middle ground for the Regis. Metal Claw can be a threat  if it manages to pull 
off a few Attack boosts. Curse is there to 
help improve Registeel's Attack  with that (removed comma)  and boost Registeel's great Defense, making it difficult to  whittle  down its HP using False Swipe. Superpower can be devastating  after a  few Attack boosts, but ends up hurting Registeel by lowering its  Attack  and Defense. 
  
If you visit the cave at the end of Iron Island without an event   Regigigas, you will find a Metal Coat at the center of the cave.
Manaphy
Manaphy is an event Pokémon, and can be obtained in many different ways.   The first method involves transferring an Egg from the Pokémon Ranger   games 
it from the Pokémon Ranger games. 
  
First, you must unlock the Manaphy mission in your Pokémon Ranger game.   In the original Pokémon Ranger game, the Manaphy mission can be  unlocked  at any time by accessing the Ranger Net after completing the  game. When  "Play a special mission" is displayed on the bottom screen,  press the R  and X buttons, as well as left on the directional pad  simultaneously.  The game will then tell you "Enter the password has  been added." Tap the  touch screen, and the game will save. The password  menu is now  unlocked, and can be found under the "Play a special  mission" option.  Upon choosing the new "Enter the password 
(removed period)"  option, you will be prompted  to enter the password for the Manaphy  mission. For the North American  version of the game the password is  P8M2-9D6F-43H7
, (comma) and for the European  version it is Mg35-Cpb8-4FW8. In Japan, you must download the mission  via a special event.
After entering the code, the game will save and must be turned off.   Restart your Pokémon Ranger game, and return to the Ranger Net. Go to   the "Play a special mission" option, and select the mission "Recover the   Precious Egg!". Complete this mission to obtain a Manaphy Egg in the   Pokémon Ranger game. Now, go to the Ranger Net once again, and select   the new "Check the Egg" option. This is the part where the second DS   system and your Pokémon Diamond or Pearl game comes in.
Turn on Pokémon Diamond/Pearl in your other DS system, and leave it at   the main menu. Now, tap the screen in your Pokémon Ranger game, and   press Send Message. A message saying 
"Pokémon Ranger is trying to  communicate
"  will appear on Diamond/Pearl, so press the A button to  confirm. Next,  select "Link with Pokémon Ranger" on the main menu. On  Pokémon Ranger,  you should now see the option to transfer. Select this  option, and the  Manaphy Egg will be transferred to your DP game. Ranger  is no longer  required. 
Once you go to a PokéMart in DP, you will find a man in a green uniform.  This is the deliveryman—
(backspaced)the  same man that gives you the items you  transfer from Pokémon Battle  Revolution, or the event Pokémon items.  Save before talking to him.  When you 
do speak with him, you 
will receive the  Manaphy Egg; its IVs and 
nature are set.
Next, go to a Pokémon Center computer, select "Bebe's PC", then "Move   Pokémon". Have a random Pokémon in the first slot of any box, and then   put your Manaphy egg in the first slot of the box that either directly   precedes or succeeds it. Go back to the first Pokémon, and let the hand   cursor hover over it. Wait until its type is displayed in the bottom   left corner of the screen for about three seconds, then press L (if the   egg is in the preceding box) or R (if it is in the succeeding box). If   you timed it correctly, you should see a flash of Manaphy's nature. If   it's no good, soft reset and get the egg again. If you like it, then   hatch it and Rare Candy it up to check IVs. If it's no good
, (comma) soft reset again,
 soft  reset, but if they're good enough for you, take it! However, due to  Manaphy being level 1, it is best 
that you still Rare Candy it up a bit and  put its stats in 
the a  IV Calculator. Due to being obtained in an egg,  Manaphy's catch rate  does not apply. However, since this Manaphy can  only be transferred to  DP, you must trade it 
from DP to Platinum 
(found myself constantly re-reading this and getting lost). 
   
  In Pokémon Ranger: Shadows of Almia and Guardian Signs, the Manaphy  Egg can be obtained 
by downloading and playing a special mission available  for download over Wi-Fi. For Shadows of Almia
, (comma)  the Manaphy mission was  available over Wi-Fi from March 20, 2008 to  June 15, 2008 for Japanese  games, November 10, 2008 to January 30, 2009  for North American games,  and November 21, 2008 to February 21, 2009  for European games. For  Guardian Signs, the Manaphy mission was  available from May 6, 2010 to  May 7, 2010 for Japanese games. Dates for  the North American and  European version have yet to be revealed. To  receive the Manaphy Egg
, (comma) you  need two DS systems. First, go to the Ranger Net option 
on in the Pokémon  Ranger game and select the “Send a Pokémon” 
button.  Then on Platinum, select  the Mystery Gift option and choose “Receive  Gift from a Friend”. The Egg  will be transferred to your Platinum game,  where you can pick it up  from the PokéMart. 
   
  The Manaphy that hatches from the Egg received from 
the Pokémon Ranger games comes at level 1. 
 
  Manaphy's Maximum Stats
Stat Max- Max Max+
HP - 13 -
Atk 6 7 7
Def 6 7 7
SpA 6 7 7
SpD 6 7 7
Spe 6 7 7
Manaphy's Moveset
Tail Glow (20 PP)
Bubble (30 PP)
Water Sport (15 PP)
 
  Total PP = 65
Darkrai
Darkrai is an event Pokémon, and can be given out in multiple ways.  In-game, it can be 
caught accessed  via the Member Card Event. First, you must  receive the Member Card  from a Nintendo Event through the Mystery Gift  option. The Member Card  was distributed over Wi-Fi from December 1, 2008  to January 15, 2009  for Japanese games and August 3, 2009 to September  13, 2009 for North  American, European, and Australian games. Once  received, you may go to  any PokéMart in Sinnoh and talk to the  deliveryman to get the item.  However, before you can activate the Member  Card event, you must have  released Cresselia and cured the sailor's son  of his nightmares with  the Lunar Wing. Once you have done 
the  aforementioned that, (comma)  go to Canalave City and head towards the Harbor Inn,  which is the last  building to the north of the Pokémon Center. After  talking to the man  inside, you will rest on the bed. When you wake up,  you will be on  Newmoon Island, where Darkrai resides. It is found in a  clearing, much  like Cresselia. Darkrai is at level 50 when you battle  it. 
Darkrai's Maximum Stats
Stat Max- Max Max+
HP - 145 -
Atk 99 110 121
Def 99 110 121
SpA 139 155 170
SpD 99 110 121
Spe 130 145 159
Darkrai's Moveset
Hypnosis (20 PP)
Faint Attack (20 PP)
Nightmare (15 PP)
Double Team (15 PP)
 
  Total PP = 70
Hypnosis and Double Team will be giving you the most trouble while  facing Darkrai. 
With Hypnosis
, Darkrai will put your Pokémon to sleep, incapacitating  them and forcing you to waste a turn waking them up
, which and gives Darkrai a  free turn to waste PP. Additionally, Darkrai's Bad Dreams ability will  cause your Pokémon to lose 12.5% of its 
max HP each turn it is asleep,  
which is more incentive to so remove your Pokémon's sleep status  
immediately as soon as possible. Double Team will raise Darkrai's evasion
, (comma) causing your  Pokémon to miss with their attacks after a few boosts and allowing  Darkrai to waste PP. Having a Pokémon 
with Odor Sleuth or Foresight will  negate any boosts it may accumulate.  Nightmare is only 
a problem if you  let your Pokémon sleep 
long enough for Darkrai to use it. Therefore,  
packing a good number of Full Heals or Awakenings 
to ensure 
that Nightmare will be 
useless it never gets the opportunity. 
Shaymin (Land Forme)
Shaymin is an event Pokémon, and can be obtained in multiple ways.  In-game
, (comma)  it can be caught via the Oak's Letter Event. First, you must  receive  Oak's Letter from a Nintendo Event through the Mystery Gift  option.  Oak's letter was distributed over Wi-Fi from April 18, 2009 to  May 11,  2009 for Japanese games and from September 28, 2009 to November  8, 2009  for North American, European
, (comma) and Australian games. Once  received, you may go to any PokéMart in Sinnoh and talk to the  deliveryman to get the item. Then, 
Fly  to the upper Pokémon League. Surf  back down to Victory Road, and  follow the path that was blocked before  you defeated the Elite Four.  Here you will meet and team up with a  trainer named Marley to get  through. Once you reach Route 224, head to  the end of the route where  you will find Professor Oak at a stone  tablet. He will ask you to write  the name of the person that helped you  most throughout your adventures  on the tablet. You can put whatever you  want here and it will extend  the route, causing lots of flowers to  appear. Shaymin will pop out to  say hi, then run away. Follow the rather  long Seabreak Path up to  Flower Paradise. Shaymin will be standing atop  a hill. 
Shaymin It is level 30 when you battle it, and has the highest  CatchRate of any legendary. 
  
Shaymin's Maximum Stats
Stat Max- Max Max+
HP - 109 -
Atk 66 74 81
Def 66 74 81
SpA 66 74 81
SpD 66 74 81
Spe 66 74 81
Shaymin's Moveset
Growth (40 PP)
Magical Leaf (20 PP)
Leech Seed (10 PP)
Synthesis (5 PP)
Total PP = 75
Leech Seed and Synthesis will restore Shaymin's HP, so you may have to   reduce its HP multiple times throughout the battle. Leech Seed is more   threatening, however, since it restores some of Shaymin's HP at the end   of each turn while it is active. As a result, it is impossible to keep   its HP at 1 while 
Leech Seed is in  effect. Breloom and Parasect are good  Catchers to use while facing  Shaymin, as they are both immune to Leech  Seed. Magical 
Leaf is only a problem if Shaymin manages to accumulate 
multiple  Special Attack boosts courtesy of Growth. 
   
  
Unless you have already done this with another event Shaymin, Once you have captured Shaymin, if you have not already done so with  another event Shaymin, head 
over to Floaroma town and speak with the  blonde-haired NPC 
with your recently caught Shaymin.  With Shaymin in your party, she will give you the Gracidea. The  Gracidea  will let you change Shaymin into its Sky Forme between 4:00  and 20:00. 
Arceus
Arceus is a special event Pokémon, and can be obtained in multiple ways.  In-game
, (comma)  it can be caught via the Azure Flute Event. First, you must  receive  the Azure Flute from a Nintendo Event through the Mystery Gift  option.  Then, proceed to any PokéMart in Sinnoh and talk to the  deliveryman to  get the item in your bag. To reach Arceus's location, you  must climb  Mt. Coronet once again, up to the Spear Pillar. Immediately,  you will  notice a mystic symbol, and the Azure Flute will begin making a  noise.  Play a melody with it, and a glowing stairway will appear. Climb  it,  and you will arrive at the Hall of Origin. Remember to save before  you  reach the top, as you will automatically approach Arceus in a  scripted  event as soon as you touch the upper platform. Here, the Alpha  Pokémon  awaits. Arceus is level 80, so 
prepare your party 
for an epic battle should be prepared.
Arceus's Maximum Stats
Stat Max- Max Max+
HP - 306 -
Atk 198 221 243
Def 198 221 243
SpA 198 221 243
SpD 198 221 243
Spe 198 221 243
Arceus's Moveset
Refresh (20 PP)
Future Sight (15 PP)
Recover (10 PP)
Hyper Beam (5 PP)
Total PP = 50
Yes, the Alpha Pokémon does indeed use Hyper Beam. While it can cause   massive damage to your Pokémon, Arceus also must recharge 
on the next turn,  giving you time to heal or lull it to sleep again. Future Sight is  nothing to laugh at either, but it is not  
as much  of a threat if your  Pokémon are appropriately leveled. Recover can get  annoying, but Refresh  is pretty much a free turn for you; after all,  you should be using the 
sleep status,  which cannot be cured with Refresh. The battle with the  Alpha Pokémon  will likely be the most difficult, but it's nothing a  high-leveled  party can't handle.
 Manaphy, Darkrai, Shaymin, and Arceus may all be given out as trades  (making it impossible to soft reset) 
(removed comma)  or Wondercard events. For a  Wondercard event, if the legendary is not  assigned a specific nature (it  would be wise to research the event you  are attending or downloading  over Wi-Fi 
beforehand),  you may reset in front of the man in green like you would  for a  Manaphy Egg. The IVs and nature are set when you pick up the  Pokémon;  Synchronize does not work in this situation. These Pokémon may  also be  received at different levels than the ones listed in their  respective  sections
. (period) As such, it is recommended to consult an online stat  calculator when you learn the level 
of your legendary 
will have when you  receive it.