Hi everyone! This is the first time I've entered competitive battling in OU. So far I've peaked at 1580-ish, but I'll try my best to make it work better with your help!
Team-building Process:
I started with Mega Scizor because it's still awesome.
Then I needed something to set up rocks, and something to remove 'em.
I needed something fast that could kill off things.
For something that had one job, Mandibuzz took a lot of damage from rocks. So I switched to Skarmory.
I had a pretty big fire weakness, so I got Heatran to fix it.
I wanted a healer, and settled for Vaporeon because it's the only water type healer in OU.
This completed my Fire-Water-Steel core.
Based on the suggestions given, I have switched Deoxys for Latios and Vaporeon for Sylveon. This is now a Fairy-Dragon-Steel Core!
Team Structure:
Latios (Offensive Defog)
Ability: Levitate
Nature: Timid
EVs: 252 Speed / 252 Sp. Atk / 4 HP
Item: Life Orb
Moves:
Draco Meteor
Psyshock
Thunder
Defog
Latios is now the defogger on this team, and unlike Skarmory he can potentially nuke something with a Life-Orb boosted STAB Draco Meteor while doing its job. Psyshock is essential STAb coverage against special walls, making Latios a very potent mixed attacker. I have chosen Thunder over Thunderbolt purely because it can KO Azumarill and actually threaten Mandibuzz.
Latios does not carry Roost, as he switches a lot due to Draco Meteor, and can always receive Wishes.
Skarmory (Physical Wall)
Ability: Sturdy
Nature: Impish
EVs: 252 Def / 224 HP / 32 Sp. Def
Item: Leftovers
Moves:
Whirlwind
Stealth Rock
Roost
Brave Bird
Skarmory can take all sorts of physical moves that threaten others in this team. Its main job is to sponge attacks, but it can also help out by setting up rocks and getting rid of boosters if needed. This is important for me because Heatran alone cannot get rid of boosters like Dragonite, Azumarill or Fighting types. Brave bird is a high-powered STAB which hits for decent damage even off an uninvested Attack stat, and more importantly ensures it isn't Taunt bait.
224 HP EVs ensure Sturdy reactivates after rocks damage and two turns Leftovers recovery. The rest is dumped into both defenses to give it as much beef as possible.
Sylveon (Healer)
Ability: Pixilate
Nature: Calm
EVs: 252 HP / 252 Sp.Def / 4 Sp. Atk
Item: Leftovers
Moves:
Wish
Protect
Heal Bell
Hyper Voice
Sylveon is the medic in this team (replacing Vaporeon), and its moves are for that purpose. Heal Bell and Wish are essential to support Scizor, Garchomp and Latios and protect them from debilitating burns. Protect allows Wish to be used reliably on Sylveon itself. The EVs give it maximum special bulk to form a ridiculously sturdy wall. Sylveon can also put an end to Rotom-W's shenanigans, something Vaporeon could not.
Heatran (Status Tank)
Ability: Flash Fire
Nature: Calm
EVs: 232 HP / 252 Sp. Def / 24 Speed
Item: Air Balloon
Moves:
Will-O-Wisp
Roar
Fire Blast
Earth Power
Heatran exists to sponge hits, burn switch-ins, phaze special boosters (which Skarmory alone cannot handle) like Gardevoir, Clefable or Latias and save Scizor from fire types. Air Balloon is still preferrred over Leftovers because that huge Earthquake weakness prevents Heatran from switching in to get an initial advantage to do its job and because it can use Wishes for later recovery anyway. Earth Power is here only for opposing Heatrans and other fire types. Since Will-O-Wisp exists specifically for burning, I have replaced Lava Plume with Fire Blast, which can help Heatran net some KOs even off an uninvested special attack stat. The EVs give maximum special bulk and enough speed to KO other Heatrans.
Garchomp (Revenge Killer)
Ability: Rough Skin
Nature: Jolly
EVs: 252 Atk. / 252 Speed / 4 HP
Item: Choice Scarf
Moves:
Dragon Claw
Earthquake
Stone Edge
Outrage
Garchomp's job is to switch in to electric moves and in general act as a revenge killer and sniper to take down specific threats, particularly Charizard X or Dragonite at +1 Speed. It has Dragon Claw and Earthquake as main STABs and Stone Edge for flying types, particularly Thundurus and Zapdos which do not invest in physical bulk. It can also clean up late-game with Outrage. It has very good bulk for an attacker so it can take a hit or two.
Scizor-M (Juggernaut)
Ability: Technician
Nature: Adamant
EVs: 252 HP / 252 Atk. / 4 Speed
Item: Scizorite
Moves:
Swords Dance
Roost
Bullet Punch
Knock Off
Everything on this team works only to set up an ideal situation for Scizor to sweep. Mega Scizor is very bulky and can take a few hits, especially after megavolving. It can act as a bulky offensive pivot, switching in on fairy types with immediate threatening momentum. Roost helps it recover health while it sets up with Swords Dance. Then it can spam Bullet Punch. Knock Off exists because it provides consistent coverage and can put a full stop to things that depend on their items, like Gliscor or Chansey, as well as remove Leftovers.
This thing is usually a good counter to most frail sweepers, managing to surprise Aegislash with Knock Off as well, and is the main threat on this team. Scizor also pairs excellently with Sylveon and Latios, killing off things on the switch.
PROBLEMS SOLVED?
This thing is still somewhat a pain. Heatran and Skarmory still can't touch it while Scizor and Garchomp just get burned before they can kill it. However, Latios is now able to scare it away or outright nuke it on most occasions because it does not fear burns, while Sylveon shrugs off anything it can throw at it while healing the team of its burn-shenanigans. However, this team does not have a hard counter (i.e. grass-type) for Rotom-W. Thunder Wave Rotom-W is apparently also a thing now, so it can cause an annoyance to Latios, but again, Sylveon fixes this.
I now have something for these. While Garchomp can't one-shot them at full health and Scizor faces grave risk of being killed by Foul Play or Heat Wave or simply being phazed off, Sylveon on the other hand has nothing to fear. Sylveon can directly threaten Mandibuzz with Hyper Voice, and takes pitifully less from Foul Play or Toxic (which can be healed off) while Zapdos is beaten at its own game by being stalled to death. Thunderbolt can at best 6HKO Sylveon if Zapdos has invested fully in Special Attack.
Fighting types no longer worry me. Although Heatran cannot burn Conkeldurr or Infernape with impunity, it now has support in the form of Sylveon which can directly assault them with Hyper Voice. Conkeldurr usually does not carry Poison Jab specifically for fairies; it rather has an elemental punch or Knock Off, both of which do nothing much to Sylveon. Scizor-M can also set up on and close down Conkeldurr if it lacks Fire Punch. Infernape isn't an issue as it can be out-sped and OHKO'ed by Garchomp or Latios.
Anti-Rotom? Not Really.
Anti-Mandibuzz/Zapdos? Check.
Hazard Control? Check.
Anti-Fighting Types? Check.
Wall-breaker that doesn't fear burn? Check.
Toxic Stall? Not Present, and hopefully not needed now.

I started with Mega Scizor because it's still awesome.



Then I needed something to set up rocks, and something to remove 'em.




I needed something fast that could kill off things.




For something that had one job, Mandibuzz took a lot of damage from rocks. So I switched to Skarmory.





I had a pretty big fire weakness, so I got Heatran to fix it.






I wanted a healer, and settled for Vaporeon because it's the only water type healer in OU.
This completed my Fire-Water-Steel core.






Based on the suggestions given, I have switched Deoxys for Latios and Vaporeon for Sylveon. This is now a Fairy-Dragon-Steel Core!
Team Structure:

Latios (Offensive Defog)
Ability: Levitate
Nature: Timid
EVs: 252 Speed / 252 Sp. Atk / 4 HP
Item: Life Orb
Moves:
Draco Meteor
Psyshock
Thunder
Defog
Latios is now the defogger on this team, and unlike Skarmory he can potentially nuke something with a Life-Orb boosted STAB Draco Meteor while doing its job. Psyshock is essential STAb coverage against special walls, making Latios a very potent mixed attacker. I have chosen Thunder over Thunderbolt purely because it can KO Azumarill and actually threaten Mandibuzz.
Latios does not carry Roost, as he switches a lot due to Draco Meteor, and can always receive Wishes.

Skarmory (Physical Wall)
Ability: Sturdy
Nature: Impish
EVs: 252 Def / 224 HP / 32 Sp. Def
Item: Leftovers
Moves:
Whirlwind
Stealth Rock
Roost
Brave Bird
Skarmory can take all sorts of physical moves that threaten others in this team. Its main job is to sponge attacks, but it can also help out by setting up rocks and getting rid of boosters if needed. This is important for me because Heatran alone cannot get rid of boosters like Dragonite, Azumarill or Fighting types. Brave bird is a high-powered STAB which hits for decent damage even off an uninvested Attack stat, and more importantly ensures it isn't Taunt bait.
224 HP EVs ensure Sturdy reactivates after rocks damage and two turns Leftovers recovery. The rest is dumped into both defenses to give it as much beef as possible.

Sylveon (Healer)
Ability: Pixilate
Nature: Calm
EVs: 252 HP / 252 Sp.Def / 4 Sp. Atk
Item: Leftovers
Moves:
Wish
Protect
Heal Bell
Hyper Voice
Sylveon is the medic in this team (replacing Vaporeon), and its moves are for that purpose. Heal Bell and Wish are essential to support Scizor, Garchomp and Latios and protect them from debilitating burns. Protect allows Wish to be used reliably on Sylveon itself. The EVs give it maximum special bulk to form a ridiculously sturdy wall. Sylveon can also put an end to Rotom-W's shenanigans, something Vaporeon could not.

Heatran (Status Tank)
Ability: Flash Fire
Nature: Calm
EVs: 232 HP / 252 Sp. Def / 24 Speed
Item: Air Balloon
Moves:
Will-O-Wisp
Roar
Fire Blast
Earth Power
Heatran exists to sponge hits, burn switch-ins, phaze special boosters (which Skarmory alone cannot handle) like Gardevoir, Clefable or Latias and save Scizor from fire types. Air Balloon is still preferrred over Leftovers because that huge Earthquake weakness prevents Heatran from switching in to get an initial advantage to do its job and because it can use Wishes for later recovery anyway. Earth Power is here only for opposing Heatrans and other fire types. Since Will-O-Wisp exists specifically for burning, I have replaced Lava Plume with Fire Blast, which can help Heatran net some KOs even off an uninvested special attack stat. The EVs give maximum special bulk and enough speed to KO other Heatrans.

Garchomp (Revenge Killer)
Ability: Rough Skin
Nature: Jolly
EVs: 252 Atk. / 252 Speed / 4 HP
Item: Choice Scarf
Moves:
Dragon Claw
Earthquake
Stone Edge
Outrage
Garchomp's job is to switch in to electric moves and in general act as a revenge killer and sniper to take down specific threats, particularly Charizard X or Dragonite at +1 Speed. It has Dragon Claw and Earthquake as main STABs and Stone Edge for flying types, particularly Thundurus and Zapdos which do not invest in physical bulk. It can also clean up late-game with Outrage. It has very good bulk for an attacker so it can take a hit or two.

Scizor-M (Juggernaut)
Ability: Technician
Nature: Adamant
EVs: 252 HP / 252 Atk. / 4 Speed
Item: Scizorite
Moves:
Swords Dance
Roost
Bullet Punch
Knock Off
Everything on this team works only to set up an ideal situation for Scizor to sweep. Mega Scizor is very bulky and can take a few hits, especially after megavolving. It can act as a bulky offensive pivot, switching in on fairy types with immediate threatening momentum. Roost helps it recover health while it sets up with Swords Dance. Then it can spam Bullet Punch. Knock Off exists because it provides consistent coverage and can put a full stop to things that depend on their items, like Gliscor or Chansey, as well as remove Leftovers.
This thing is usually a good counter to most frail sweepers, managing to surprise Aegislash with Knock Off as well, and is the main threat on this team. Scizor also pairs excellently with Sylveon and Latios, killing off things on the switch.
PROBLEMS SOLVED?

This thing is still somewhat a pain. Heatran and Skarmory still can't touch it while Scizor and Garchomp just get burned before they can kill it. However, Latios is now able to scare it away or outright nuke it on most occasions because it does not fear burns, while Sylveon shrugs off anything it can throw at it while healing the team of its burn-shenanigans. However, this team does not have a hard counter (i.e. grass-type) for Rotom-W. Thunder Wave Rotom-W is apparently also a thing now, so it can cause an annoyance to Latios, but again, Sylveon fixes this.


I now have something for these. While Garchomp can't one-shot them at full health and Scizor faces grave risk of being killed by Foul Play or Heat Wave or simply being phazed off, Sylveon on the other hand has nothing to fear. Sylveon can directly threaten Mandibuzz with Hyper Voice, and takes pitifully less from Foul Play or Toxic (which can be healed off) while Zapdos is beaten at its own game by being stalled to death. Thunderbolt can at best 6HKO Sylveon if Zapdos has invested fully in Special Attack.


Fighting types no longer worry me. Although Heatran cannot burn Conkeldurr or Infernape with impunity, it now has support in the form of Sylveon which can directly assault them with Hyper Voice. Conkeldurr usually does not carry Poison Jab specifically for fairies; it rather has an elemental punch or Knock Off, both of which do nothing much to Sylveon. Scizor-M can also set up on and close down Conkeldurr if it lacks Fire Punch. Infernape isn't an issue as it can be out-sped and OHKO'ed by Garchomp or Latios.
Anti-Rotom? Not Really.
Anti-Mandibuzz/Zapdos? Check.
Hazard Control? Check.
Anti-Fighting Types? Check.
Wall-breaker that doesn't fear burn? Check.
Toxic Stall? Not Present, and hopefully not needed now.
Last edited: