My idea for better TriHards

Darkrai

Ability: Bad Dreams

EVs: 84 HP / 68 Atk / 56 Def / 24 SpA / 148 SpD / 128 Spe

Bold Nature

- Nightmare

- Dark Void

- Dream Eater

- Foul Play

Entei

Ability: Pressure

EVs: 128 HP / 132 Atk / 40 Def / 56 SpA / 32 SpD / 120 Spe

Hasty Nature

- Fire Fang

- Headbutt

- Roar

- Shadow Ball

Deoxys

Ability: Pressure

EVs: 120 Def / 100 SpA / 120 SpD / 168 Spe

Quiet Nature

- Nasty Plot

- Dark Pulse

- Psycho Boost

- Charge Beam

Deoxys-Attack

Ability: Pressure

EVs: 16 HP / 120 Atk / 72 Def / 120 SpA / 180 Spe

Naughty Nature

- Energy Ball

- Superpower

- Psychic

- Shadow Ball

OpieOP (Deoxys-Defense)

Ability: Pressure

EVs: 80 HP / 120 Def / 108 SpA / 80 SpD / 120 Spe

Serious Nature

- Psyshock

- Shadow Ball

- Calm Mind

- Substitute

Volcania (Deoxys-Speed)

Ability: Pressure

EVs: 40 HP / 120 Atk / 96 Def / 80 SpA / 52 SpD / 120 Spe

- Psycho Boost

- Nasty Plot

- Drain Punch

- Ice Beam

Regigigas

Ability: Slow Start

EVs: 96 Atk / 160 Def / 180 SpD / 72 Spe

Timid Nature

- Drain Punch

- Crush Grip

- Thunder Punch

- Heavy Slam

NOTE: For deoxys I think it would be a good idea to make it so you can choose the form in some way. like !match x,y,386-0/a,b,c

You cant use multiple forms of deoxys so no deoxys vs deoxys or Deoxys, Deoxys, Deoxys vs Entei, Darkrai, and Regigigas.