Mega-Diancie for President (ORAS) Ubers

Darkrai @ Life Orb
Ability: Bad Dreams
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Dark Pulse
- Sludge Bomb
- Nasty Plot
- Dark Void

Groudon-Primal @ Red Orb
Ability: Desolate Land
EVs: 248 HP / 56 Def / 200 SpD / 4 Spe
Impish Nature
- Precipice Blades
- Fire Punch
- Thunder Wave
- Stealth Rock

Arceus @ Life Orb
Ability: Multitype
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Extreme Speed
- Earthquake
- Shadow Claw
- Swords Dance

Diancie-Mega @ Diancite
Ability: Magic Bounce
EVs: 4 Atk / 252 SpA / 252 Spe
Naive Nature
- Moonblast
- Diamond Storm
- Earth Power
- Protect

Giratina-Origin @ Griseous Orb
Ability: Levitate
EVs: 248 HP / 200 Def / 60 SpD
Bold Nature
IVs: 0 Atk
- Draco Meteor
- Shadow Ball
- Will-O-Wisp
- Defog

Xerneas @ Choice Scarf
Ability: Fairy Aura
EVs: 32 Def / 252 SpA / 224 Spe
Modest Nature
IVs: 0 Atk
- Moonblast
- Thunder
- Focus Blast
- Sleep Talk