Groudon @ Toxic Orb  
Ability: Poison Heal  
EVs: 252 HP / 176 Atk / 80 Spe  
Adamant Nature  
- Swords Dance  
- Precipice Blades  
- Stone Edge  
- Protect  

Regigigas @ Toxic Orb  
Ability: Poison Heal  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Facade  
- Knock Off  
- Thunder Wave  
- Protect  

Arceus-Dark @ Dread Plate  
Ability: Fur Coat  
EVs: 252 HP / 252 Def / 4 Spe  
Bold Nature  
- Iron Defense  
- Foul Play  
- Dragon Tail  
- Recover  

Corviknight @ Ability Shield  
Ability: Magic Bounce  
EVs: 252 HP / 252 Def / 4 SpD  
Impish Nature  
IVs: 0 Atk  
- Iron Defense  
- Body Press  
- Defog  
- Roost  

Magearna @ Leftovers  
Ability: Regenerator  
EVs: 252 HP / 4 Def / 252 SpD  
Sassy Nature  
IVs: 0 Atk / 0 Spe  
- Volt Switch  
- Ice Beam  
- Spikes  
- Encore  

Eternatus @ Ability Shield  
Ability: Ice Scales  
EVs: 80 HP / 252 SpD / 176 Spe  
Timid Nature  
- Sludge Bomb  
- Flamethrower  
- Dragon Tail  
- Recover