Hi Joey, few explanations as to how to use this team :

- The idea is to lead Primal-Kyogre, which is 28IV's speed to always win the weather war against Groudon. Water-Spout allows you to kill soemthing immediately (or 2hit KOS, even Chansey) if your opponent leads with Groudon. The EV's spread lets you take a lot of hits (+2 extreme speed from e-killer ; +2 moonblast from Xerneas ; skystrike from Rayquasa...).
- Scarf lonely Rayquaza is the key to winning games : it ousteepds everything, and hits really hard (2hit kos most of defensive arceus-fairy). Waterfall is there to kill Primal-Groudon.
- Xerneas is extremely important against Marshadow's matchups, wich this team struugles against. You absolutely have to keep it alive in order not to lose. Same with E-Killer ; it takes a +4 extreme speed.

Hope you'll enjoy!

Rayquaza @ Choice Scarf
Ability: Air Lock
EVs: 252 Atk / 4 SpA / 252 Spe
Lonely Nature
- Dragon Ascent
- Draco Meteor
- V-create
- Waterfall

Xerneas @ Power Herb
Ability: Fairy Aura
EVs: 252 HP / 252 Def / 4 SpA
Bold Nature
IVs: 0 Atk
- Geomancy
- Thunder
- Hidden Power [Ground]
- Moonblast

Groudon @ Red Orb
Ability: Drought
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Fire Blast
- Earth Power
- Hidden Power [Ice]
- Rock Polish

Kyogre-Primal @ Blue Orb
Ability: Primordial Sea
EVs: 164 HP / 252 Def / 92 SpA
Modest Nature
IVs: 0 Atk / 28 Spe
- Origin Pulse
- Thunder
- Ice Beam
- Water Spout

Arceus-Dark @ Dread Plate
Ability: Multitype
EVs: 252 HP / 4 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Judgment
- Calm Mind
- Recover
- Defog

Aegislash @ Leftovers
Ability: Stance Change
EVs: 252 HP / 4 Atk / 252 SpD
Sassy Nature
IVs: 0 Spe
- Toxic
- King's Shield
- Shadow Ball
- Gyro Ball