Ditto @ Choice Scarf  
Ability: Imposter  
EVs: 252 HP / 252 Def / 4 SpD  
Relaxed Nature  
IVs: 30 Atk  
- Transform  

Ho-Oh @ Choice Band  
Ability: Regenerator  
EVs: 4 HP / 252 Atk / 252 Spe  
Jolly Nature  
- Sacred Fire  
- Brave Bird  
- Earthquake  
- Sleep Talk  

Diancie-Mega @ Diancite  
Ability: Clear Body  
EVs: 160 HP / 96 SpA  
Timid Nature  
IVs: 0 Atk  
- Stealth Rock  
- Protect  
- Moonblast  
- Toxic  

Groudon-Primal @ Red Orb  
Ability: Desolate Land  
EVs: 32 Atk / 224 SpA / 252 Spe  
Hasty Nature  
- Swords Dance  
- Eruption  
- Precipice Blades  
- Rock Tomb  

Arceus @ Earth Plate  
Ability: Multitype  
EVs: 248 HP / 56 Def / 204 Spe  
Timid Nature  
IVs: 0 Atk  
- Judgment  
- Ice Beam  
- Recover  
- Defog  

Ferrothorn (F) @ Leftovers  
Ability: Iron Barbs  
EVs: 248 HP / 8 Def / 252 SpD  
Sassy Nature  
IVs: 0 Spe  
- Leech Seed  
- Protect  
- Spikes  
- Gyro Ball