Arceus @ Splash Plate
Ability: Multitype
EVs: 252 HP / 104 Def / 152 Spe
Bold Nature
- Judgment
- fill x3
 
Ceruledge calcs:
 252+ Atk Lucarionite Adaptability Ceruledge Poltergeist vs. 252 HP / 104+ Def Arceus-???: 220-260 (49.5 - 58.5%) -- 98.8% chance to 2HK0
 +2 252 Atk Lucarionite Adaptability Ceruledge Poltergeist vs. 252 HP / 104+ Def Arceus-???: 398-470 (89.6 - 105.8%) -- 37.5% chance to OHKO

Arceus @ Splash Plate
Ability: Multitype
EVs: 124 HP / 232 Def / 152 Spe
Bold Nature
- Judgment
- fill x3
 
Ceruledge calcs (104/252+ is the exact same calc but technically worse defensively):
252+ Atk Lucarionite Adaptability Ceruledge Poltergeist vs. 124 HP / 232+ Def Arceus-???: 198-234 (48 - 56.7%) -- 89.1% chance to 2HKO
+2 252 Atk Lucarionite Adaptability Ceruledge Poltergeist vs. 124 HP / 232+ Def Arceus-???: 360-424 (87.3 - 102.9%) -- 18.8% chance to OHKO