Here comes an old set:
WRECK EVERYTHING AS POSSIBLE IN 5 TURNS (Choice Specs)
Item: Choice Specs
Nature: Modest
EVs: 252 HP/252 SpA/4 Spe
Moves:
- Water Spout
- Surf
- Ice Beam
- Thunder
The wallbreaker. It is back. For more. I couldn't think of a better name, but I considered the fact that Water Spout has a mediocre 5 PP (no PP Up) and that Drizzle now always lasts 5 turns.
Anyways, Water Spout and Thunder are fairly obvious since they're incredible in the rain. Surf can be used over Water Spout after Kyogre gets weakened and Ice Beam destroys Shaymin-S and heavily dents Arceus-Grass (the latter may force Kyogre with a Grass-type Judgment, however).
CALCS (after Kyogre is hit by Stealth Rock in the switch, meaning 131 BP):
- 248/252 (Careful) Giratina: 36.97% - 43.53%
- 0/0 Palkia: 38.94% - 45.79%
- 4/252 (Calm) Chansey: 42.52% - 50.16% (Possible 2HKO)
- 252/224 (Calm) Tentacruel: 52.2% - 61.5% (Possible 2HKO)
- 252/252 (Sassy) Ferrothorn: 53.98% - 63.64% (guaranteed 2HKO)
- 252/4 Arceus-Grass: 56.08% - 66.22% (guaranteed 2HKO)
- 104/0 Zekrom: 79.84% - 94.01% (Possible OHKO after Stealth Rock)
- 252/80 Lugia: 91.59%+ (OHKO after Stealth Rock)
Chansey has a guaranteed 2HKO after Stealth Rock if it is running a Bold nature, while Arceus that doesn't resist Water Spout gets OHKOd. Tentacruel running Protect and Rain Dish survives the 2HKO, however.
Due to my Kyogre being Timid, I'm not sure if it can still be used with Choice Specs and a different EV spread.