Diancie-Mega @ Diancite  
Ability: Magic Bounce  
EVs: 240 HP / 16 Def / 252 Spe  
Jolly / Timid Nature  
- Stealth Rock  
- Substitute  
- Endeavor  
- Diamond Storm / Moonblast

Magearna @ Aguav Berry / Leftovers / Custap Berry
Ability: Soul-Heart  
EVs: 248 HP / 72 Def / 136 SpA / 8 SpD / 44 Spe  
Modest Nature  
IVs: 0 Atk  
- Calm Mind  
- Fleur Cannon / Ice Beam
- Focus Blast / Aura Sphere
- Thunderbolt