>>49334819For references, the weakness/resistances of a 'all type' Pokémon are as follows:
Normal: Immune, 1/4 if immunity negated
Fighting: Immune, 1x if immunity negated
Flying: 1x
Poison: Immune, 1/4 if immunity negated
Ground: Immune, 8x if immunity negated
Rock: 2x
Bug: 1/16
Ghost: Immune, 2x if immunity negated
Steel: 1/2
Fire: 1x
Water: 1x
Grass: 1/16
Electric: Immune, 1/2 if immunity negated
Psychic: Immune, 1x if immunity negated
Ice: 1x
Dragon: Immune, 1x if immunity negated
Dark: 1/2
Fairy: 1x
Best strategies vs. an all-type Arceus are Rock, or, best of all, Gravity+ ground move.