Dialga
@Chesto Berry
Quiet 252 HP / 252 SpA / 4 Def
Rest
Trick Room
Dragon Pulse
Flamethrower / Blizzard
Standard Dialga lead: Trick Room setup, flamethrower on steel types, Dragon Pulse for STAB, blahblahblah.
Infernape
@Focus Sash
Brave 252 Atk / 64 SpA / 192 HP
Fake Out
Low Kick
Heat Wave
Close Combat / Grass Knot
Key member of the team. Fake Out to hinder opponent's set up (and hopefully support Dialga's Trick Room set up), Heat Wave can hit both enemies, and is super effective to Metagross and Abomasnow. Close Combat can be used as a general sweeping move, getting in a kill before death, or taking down the high defense pokes, or Grass Knot can be used if I'm scared of Rain Dancers. But the best part of Infernape is Low Kick; it has awesome power against nearly everything that seems popular: Dialga, Ttar, Obama, Palkia, and Smeargle, covering the majority of Pokemon. The only thing it can't cover is Mewtwo because Psychic is too cool for Infernape.
Giratina-O
Griseous Orb
Quiet 252 SpA / 12 HP / 248 SpDef
Draco Meteor
Energy Ball
Shadow Ball
Protect
Nearing the end of the game, Giratina's Origin forme can rape and pillage the enemy's team with high damage attacks like Shadow Ball and Draco Meteor. Energy Ball can be used to counter Kyogres.
Metagross
Shuca Berry
Brave 252 HP / 252 Atk / 6 Def
Explosion
Earthquake
Thunder Punch
Meteor Mash
Earthquake hits the opponent's team, as does Explosion in a last chance move to destroy the opponent. Thunder Punch for waters and flying, and Meteor Mash as a general use, high damage attack.
All EVs/IVs are set to work fairly well with Trick Room. Changed Palkia and Abomasnow to Giratina and Metagross. I now have access to Earthquake and Explosion abuse, and can use Giratina to take out Mewtwo and other Giratinas, or any other Psychics/Ghosts.
Criticism and recommendations greatly appreciated. :)