Kyogre

The choice of nature depends on your preference. Timid lets Kyogre outspeed other Kyogre, Groudon, most Dialga, some Palkia, and Lugia. Modest will always 2HKO Blissey with Water Spout, and it lets you OHKO Lugia a bit more often, too. It can also 2HKO the standard Latias, who is one of Kyogre's only true counters, with Stealth Rock in play.

If you are running a Modest nature, it is advised to use an alternate EV spread of 240 HP / 244 Special Attack / 24 Speed. Kyogre is one of the slowest Ubers (not counting Wobbuffet), and Speed does not help it much. 24 Speed here allows it to outrun Tyranitar and possibly some other base 90 Speed Ubers (Groudon, Kyogre, Dialga, Giratina, Deoxys-D, Ho-Oh) that don't pump their Speed.

When using Choice Specs Kyogre, it is often a good idea to use Ice Beam before any other attack if you do not know the opponent's whole team. This is because the two most common Kyogre switch-ins, Palkia and Latias, are both 2HKOed by Ice Beam if they have taken damage from Stealth Rock.

Choice Specs Kyogre will have problems sweeping with Water Spout if Palkia and Latias are still around, and additionally, Quagsire can wall it thanks to Water Absorb and its Ground typing. Finally, a specially defensive Ludicolo is arguably the only true Choice Specs Kyogre counter, as it can stall out Thunders thanks to Protect, Rain Dish, and Leech Seed. Choice Band Tyranitar with 56 Attack EVs can easily take care of Latias, as Pursuit will 2HKO it if it doesn’t switch out, and Crunch will easily OHKO Latias. Be warned that if Latias is carrying Grass Knot, the standard Careful 252 HP / 200 SpD Tyranitar has a 80% chance of being 2HKOed after taking damage from Stealth Rock. Scizor can work in a similar manner if Latias lacks Thunder, thanks to a Pursuit of its own and STAB U-turn. A specially defensive Scizor also has the bonus ability to switch into a defensive Ludicolo's Grass Knot and threaten it with U-turn. Quagsire poses no threat to Scizor as well. Finally, Palkia can be dealt with by switching Garchomp into its Thunder. Be careful, as some Palkia may opt to use a Dragon move instead, which will OHKO Garchomp. A defensive Dialga can work in a similar manner, and Dialga will survive Palkia's Dragon-type assaults (unless Palkia has Choice Specs). Thanks to Blissey's massive Special Defense and HP, she can work well with Choice Specs Kyogre, as she can switch into Latias's and Palkia's powerful special attacks and wall them (be careful with Palkia, however, as some of them are mixed). Giratina-O complements Choice Specs Kyogre very well offensively and defensively. When facing most stall teams, their only hope against Giratina-O is Latias. If Giratina-O has set up one Calm Mind, it can OHKO Latias after it switches into Stealth Rock, while Latias will be unable to KO Giratina-O. With Latias down, Choice Specs Kyogre can devastate the stall team, as Latias is often their only hope against Choice Specs Kyogre. Giratina-O also sports a resistance to Electric and Grass moves, and thus can set up on these moves if they are Choiced.

Although Groudon most certainly cannot switch into Choice Specs Kyogre's powerful Water- and Ice-type attacks, it can switch into Kyogre's Thunder, use Rock Polish on the switch, and attempt to sweep. Because of this, Choice Scarf Shaymin-S makes an excellent offensive teammate for Kyogre, as it can outspeed an Adamant Groudon after it has used Rock Polish once and will OHKO it with a STAB Seed Flare. Garchomp can utilize a similar tactic when switching into Thunders, but dealing with Garchomp can be much trickier, as Garchomp commonly holds Choice items of its own, allowing it to often hurt your switch-in badly. Skarmory can be used as a way to ward off Garchomp, as it is immune to Garchomp's Earthquake, resists Outrage, and will be able to withstand Fire attacks more easily thanks to Kyogre's rain. Bronzong also works in a similar manner. Both Skarmory and Bronzong can beat Groudon that lack Fire Punch, as they can set up entry hazards, and Bronzong can 3HKO Groudon with Grass Knot. Something important to note is that once Kyogre is at 75% of its health, specially defensive Dialga can survive and outstall Kyogre's Water Spouts via Pressure and Rest (though Dialga is still 3HKOed by Surf). Because of this, a Groudon can be a useful teammate for Kyogre, as most specially defensive Dialga will have Bulk Up; thus they will have trouble beating Support Groudon while Groudon will inflict severe damage on Dialga with STAB Earthquakes.

Be careful not to constantly switch Kyogre into attacks, as even the smallest shots can decrease Water Spout's power. Sadly, however, there is no way to avoid taking damage from Stealth Rock, Spikes, or Toxic Spikes, unless you use a Rapid Spinner, which may not even get to Spin due to the presence of Giratina. Kyogre needs to be at 80% health or higher to keep Water Spout more powerful than Hydro Pump, or 64%+ health to keep it stronger than Surf.

Waterfall and Aqua Tail are options on this set to severely dent Blissey. Kyogre needs 180 Attack EVs with either a Mild or Rash nature to guarantee a 2HKO on Blissey with Aqua Tail. Waterfall won't 2HKO, but its chance of flinch will keep Blissey away from it.

You have two options for the nature here (assuming you don't use a physical Water move): Modest or Timid. Modest gives Kyogre extra power, but Timid is often the better choice because it allows Kyogre to outrun Naive / Hasty Deoxys-A, Adamant Dragon Danced Rayquaza, and other Modest Choice Scarf Kyogre. It all depends on what you desire for the team.

In addition to the problems Choice Specs Kyogre has with Palkia, Latias, and Ludicolo, Choice Scarf Kyogre has issues with Blissey, Giratina, and specially defensive Dialga. Scizor can easily deal with Latias without Thunder and Ludicolo without Surf. Bulk Up Dialga is an excellent teammate for Choice Scarf Kyogre. This is because Bulk Up Dialga can easily set up on both Blissey and Giratina. Defensive Groudon can usually handle specially defensive Dialga, as many are Bulk Up variants. If you are worried about defensive Dialga with special attacks, a Blissey of your own can withstand its attacks.

Despite being one of the slowest Ubers, Kyogre gets good usage out of a Timid nature, letting it tie at worst with Groudon and other non-Choice Scarf Kyogre and outspeed the vast majority of Dialga and Rayquaza. It can also outrun Lugia that invest more EVs into their defenses than Speed and 2HKO it with +1 Thunder. If Speed is not as important as power, Modest is an acceptable nature. When using Modest, Kyogre's EV spread should be 124 HP / 252 SpA / 132 Spe. The Speed allows Kyogre to outspeed most Adamant Rock Polish Groudon before they boost their Speed.

Despite Calm Mind Kyogre's power, Kyogre will have a difficult time getting past Blissey, Latias, and Latios. Blissey can use Toxic, Protect, and Wish to eventually stall Kyogre to death. Because of this, Wobbuffet can be a very effective teammate for Calm Mind Kyogre. Wobbuffet can trap Blissey and use Tickle to lower its Defense. After being Tickled two times, a fleeing Blissey will be OHKOed by a Pursuit coming from a neutral-natured Choice Band Tyranitar with 56 Attack EVs. After being Tickled four times, a fleeing Blissey will OHKOed by a Pursuit coming from an Adamant Life Orbed Scizor with 100 Attack EVs. With Blissey out of the way, Kyogre will often have a much easier time sweeping. Wobbuffet is also able to help set up Kyogre thanks to Encore and Shadow Tag. A Careful Tyranitar with 252 HP EVs and 200 Special Defense EVs is capable of switching into any of Latias's or Latios's special attacks bar Grass Knot and either OHKO them with Crunch or OHKO them with Pursuit as they switch out. Scizor can also switch into Latias without Thunder and threaten to OHKO them with U-turn.

If you opt for Ice Beam in the last slot, Kyogre will be unable to break through opposing Kyogre. Because of this, Latias can be a good teammate for Substitute Kyogre. Latias can easily switch into an opposing Kyogre's Thunder, and either force it out with the threat of Grass Knot or Thunder, or use Calm Mind to set up on Kyogre. In a similar manner, a specially defensive Bulk Up Dialga can switch into a Choiced Kyogre's Thunder and set up on it. If Substitute Kyogre uses Thunder over Ice Beam, Kyogre will have even more trouble with Latias and Latios then usual, so Choice Band Tyranitar and Choice Band Scizor with heavy Special Defense investment make good partners. Like the last set, Kyogre will greatly benefit from Wobbuffet's support, as Wobbuffet can use Encore to help Kyogre set up a Substitute.

This set runs into major problems against Latias and Latios, who resist Surf and are capable of Calm Minding alongside Kyogre. As usual, Scizor or Tyranitar can be used to beat most Latias or Latios. Rayquaza is a problem as well: with a Water resistance and Air Lock to nullify rain, it easily sets up a Dragon Dance or Swords Dance. Choice Specs Kyogre can also use Thunder to do some serious damage as well. Because of this, Choice Scarf Garchomp is a very good teammate with Boosting Tank Kyogre. Garchomp can switch into Rayquaza as it attempts to set up, and either force it to switch out or OHKO it with STAB super effective Dragon moves. Thanks to Garchomp's Ground typing, it can also absorb Thunders from Choiced Pokémon such as Kyogre and force them to switch out. Finally, Choice Scarf Garchomp is also able to outspeed and KO opposing Latias and Latios with Outrage.

Lum Berry on this set is important for two reasons. Firstly, if Darkrai tries to use Dark Void, your status will remain intact and you can subsequently OHKO with Surf. Second, the lack of Leftovers recovery when using a Berry means that you can bluff a Choice Scarf, and as such, you won't need to fear getting tricked a Choice Scarf by opposing Trick Choice Scarf Darkrai. It will also help with taking on Groudon's Thunder Waves, and after that, you can OHKO with a rain-boosted Surf.

The EVs here are quite simple, yet important. It is critical you have absolutely no Speed EVs and a 30 Speed IV on this Kyogre, as it will let it get the rain up when faced against Groudon. The remaining EVs are put into Special Attack to do as much damage as possible.

Note that this set can be used as a mid-game sweeper, not only as a lead. Thunder Wave is incredibly helpful in taking down some counters. It's normally outclassed by the Calm Mind set in terms of sweeping, though, as that set can build up damage over time. If you do decide to go this route, though, run Expert Belt over Lum Berry, as it can still bluff a Choice item.

The main selling point of Thunder Wave Kyogre is its ability to help slower sweepers who have problems with Latias and Palkia by paralyzing them, as both are common switch-ins to Kyogre. A good teammate for this lead is a mixed Palkia, as it benefits from both the paralysis and the fact Kyogre and Palkia have similar counters means that if you immobilize a Latias or opposing Choice Scarf Palkia, it is easier for Palkia to sweep. Another Pokémon who benefits from this is Swords Dance Garchomp. If Kyogre is able to paralyze either Latias or Choice Scarf Palkia, Garchomp will have a significantly easier time sweeping. Dragon Dance Rayquaza also greatly benefits from this particular Kyogre, as Choice Scarf Palkia will no longer be able to stop a sweep from Rayquaza when paralyzed. Finally, Giratina-O is particularly useful with Thunder Wave Kyogre, because Palkia and Latias will be hard pressed to stop its sweeps if they are paralyzed.

This Kyogre appreciates Toxic Spikes support, as well as teammates to prevent Latias and Latios from using Calm Mind alongside Kyogre and consequently beating it with Thunder or Grass Knot. With Toxic Spikes, Kyogre can focus on gaining more Calm Minds against things like Blissey and Palkia while the poison withers them away into nothingness. Forretress sets up Toxic Spikes very easily thanks to its many resistances and draws Fire-type attacks that Kyogre can switch into. Choice Scarf Tyranitar can easily come in on Latias and Latios who lack Grass Knot and Pursuit as they switch or KO them with a fast Crunch. Scizor and Metagross are also solid Pursuit users to consider for the job.

Most boosted Electric-type attacks, such as Choice Specs Thunder from the likes of Dialga, Palkia, and enemy Kyogre will 2HKO this Kyogre even after a Calm Mind boost. Furthermore, physical variants of Dialga and Palkia can 2HKO Kyogre before it can even set up. Garchomp boasts an immunity to Electric-type attacks and can use his powerful STAB Outrage and Earthquake to destroy the aforementioned Pokemon. Garchomp also baits Ice-type attacks that Kyogre can set up on. Physical Dialga and Palkia can be handled easily by Groudon, who can also take Electric-type attacks aimed at Kyogre. Lugia can work as well by setting up Reflect to help Kyogre take physical attacks as it sets up. Both Groudon and Lugia can provide paralysis support to make up for Kyogre's middling Speed, but it's not recommended with Toxic Spikes on the same team.

Even with virtually no investment in Attack, a simple Life Orb ensures that Waterfall will 2HKO Blissey. Life Orb has the added benefit of boosting both Surf and Thunder as well, which can be helpful when facing physically defensive foes such as Groudon. Thunder is usually given the nod over Ice Beam because it hits opposing Kyogre and does more damage to Lugia, but Ice Beam is an option if Dragon-types trouble you. Life Orb is meant to be used with a Hasty nature to give Kyogre power without sacrificing Speed, but Sea Incense is a worthy alternative if the recoil turns you off. When using Sea Incense, it's recommended to use a Mild nature with a spread of 192 HP / 60 Atk / 252 SpA to ensure a 2HKO on Blissey with Waterfall.

There are a number of Pokemon that benefit from Kyogre's ability to remove Blissey and cripple Latias and Palkia. Taunt + Calm Mind Mewtwo is an excellent example; not only can it sweep with greater ease with Blissey out of the picture, it also doesn't have to worry about being revenge killed by Palkia if Palkia is paralyzed. A Calm Mind Latias of your own is another great partner, especially if you run Ice Beam on Kyogre, as it can counter opposing Kyogre and sweep once Blissey is eliminated. Although this set struggles against typical Kyogre counters such as Palkia, Latias, and Ludicolo, the use of Thunder Wave can help mitigate this weakness. However, Quagsire deserves mention because it completely walls all of Kyogre's attacks outside of Ice Beam. Scizor is a good partner to beat Quagsire, and it also serves as a great Palkia and Latias check if Kyogre is unable to paralyze them.