Rayquaza-Mega @ Life Orb  
Ability: Triage  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Tail Glow  
- Oblivion Wing  
- Giga Drain  
- Moongeist Beam  

Gengar-Mega @ Spooky Plate  
Ability: Teravolt  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Shell Smash  
- Judgment  
- Sludge Bomb  
- Stealth Rock  

Arceus-Psychic @ Spooky Plate  
Ability: Speed Boost  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Tail Glow  
- Boomburst  
- Judgment  
- Taunt  

Dialga @ Steelium Z  
Ability: Magic Bounce  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 248 Spe  
Calm Nature  
IVs: 0 Atk  
- Tail Glow  
- Doom Desire  
- Core Enforcer  
- Shore Up  

Diancie-Mega @ Leftovers  
Ability: Pixilate  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Rash Nature  
- Boomburst  
- Extreme Speed  
- Thousand Waves  
- Substitute  

Yveltal @ Safety Goggles  
Ability: Unaware  
EVs: 248 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Sassy Nature  
- Revelation Dance  
- Spectral Thief  
- Rapid Spin  
- Slack Off