Groudon, because his Primal Ability cancels out his weakness to water
Kyogre already resists fire-types, which means making them useless is bordering on redundant
Plus, Thunder gets 100% accuracy in rain, so good job making it even easier to hit you!
Rayquaza has a special place in my heart due to the fact she was my first pokemon I ever got to level 100
Plus, she was the first (and so far, only) Pokémon that I solo'd the Elite Four with
Yeah, I give genders to legendary pokemon, sue me...