Swampert-Mega @ Safety Goggles  
Ability: Wonder Guard  
EVs: 248 HP / 4 Atk / 252 Def / 4 SpD  
Relaxed Nature  
IVs: 0 Spe  
- Parting Shot  
- Roost  
- Defog  
- Thousand Waves  

Latios-Mega (M) @ Soul Dew  
Ability: Wonder Guard  
EVs: 252 SpA / 4 SpD / 252 Spe  
Modest Nature  
IVs: 1 Atk / 30 Def / 30 SpA / 30 SpD  
- Shell Smash  
- Freeze-Dry  
- Hidden Power [Poison]  
- Searing Shot  

Xerneas @ Leftovers  
Ability: Wonder Guard  
EVs: 248 HP / 252 SpA / 8 SpD  
Modest Nature  
IVs: 0 Atk  
- Substitute  
- Baton Pass  
- Moonblast  
- Magic Coat  

Groudon-Primal @ Choice Band  
Ability: Mold Breaker  
EVs: 240 HP / 252 Atk / 16 Spe  
Adamant Nature  
- U-turn  
- V-create  
- Thousand Arrows  
- Ice Shard  

Slaking @ Silk Scarf  
Ability: Shadow Tag  
EVs: 252 Atk / 252 Def / 4 SpD  
Adamant Nature  
- Fake Out  
- Extreme Speed  
- Low Kick  
- Stealth Rock  

Giratina @ Safety Goggles  
Ability: Prankster  
EVs: 248 HP / 252 Def / 8 Spe  
Bold Nature  
IVs: 0 Atk  
- Will-O-Wisp  
- Baton Pass  
- Encore  
- Roost