Groudon-Primal @ Life Orb  
Ability: Magic Guard  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Naughty Nature  
- Mind Blown  
- Freeze-Dry  
- Sunsteel Strike  
- Shell Smash  

Houndoom-Mega @ Choice Scarf  
Ability: Wonder Guard  
EVs: 248 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Blue Flare  
- Menacing Moonraze Maelstrom  
- Toxic Spikes  
- Trick  

Meloetta @ Leppa Berry  
Ability: Harvest  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 30 HP / 0 Atk  
- Extreme Evoboost  
- Light That Burns the Sky  
- Menacing Moonraze Maelstrom  
- Recover  

Mewtwo-Mega-Y @ Focus Sash  
Ability: Protean  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Mild Nature  
IVs: 30 HP  
- Sunsteel Strike  
- Moongeist Beam  
- Moonblast  
- Shell Smash  

Swampert-Mega @ Safety Goggles  
Ability: Wonder Guard  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Impish Nature  
IVs: 30 HP  
- Spectral Thief  
- Baton Pass  
- Thousand Waves  
- Recover  

Yveltal @ Focus Sash  
Ability: Magic Guard  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Adamant Nature  
- Pursuit  
- Power Trip  
- Sunsteel Strike  
- Extreme Evoboost