
Groudon @ Leftovers
Drought
Impish 252 HP / 252 Def / 4 Spe
- Earthquake
- Stone Edge
- Stealth Rock
- Roar
and

Skarmory @ Leftovers
Sturdy
Careful 252 HP / 4 Def / 252 SpD
- Whirlwind
- Roost
- Toxic / Taunt
- Spikes / Taunt
A nice pair of defensive pivots that can be slotted nicely into an offensive team. Extreme Killer Arceus can be a real threat to offensive teams, and this pair (especially if a Kyogre is partnered to remove Skarmory's weakness to the odd Overheat when you need it) should be more than enough to handle it, while also functioning as a general defensive tool or hazard setters. The core is weak to the likes of Kyurem-W and Latias, of course, but those can be handled well enough by teammates. An Ice-type resistant Pokemon is especially important for handling Kyurem-W. But it's still a pretty nice standalone core.