Koraidon + Mega Diancie + Choice Band Ho-Oh

Koraidon @ Choice Scarf
Ability: Orichalcum Pulse
Tera Type: Fighting
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Dragon Claw
- Flare Blitz
- U-turn

Ho-Oh @ Choice Band
Ability: Regenerator
Tera Type: Fire
EVs: 248 HP / 196 Atk / 52 SpD / 12 Spe
Adamant Nature
- Flare Blitz
- Brave Bird
- Earthquake
- Whirlwind

Diancie-Mega @ Diancite
Ability: Magic Bounce
Tera Type: Rock
EVs: 24 Atk / 232 SpA / 252 Spe
Naive Nature
- Diamond Storm
- Moonblast
- Earth Power
- Stealth Rock