Mega Xerneas would be the check to everything, Ultra Necrozma, Mega Rayquaza, Miraidon, Koraidon, and many more of the strongest pokemon making it practically unbeatable, I mean without a mega evolution it's in the AG tier so what happens if it gets a mega.
Solution: Dusk Mane Necrozma Ability: Full Metal Body + Prism Armor ( Shadow Shield instead Full Metal Body if Dawn Wings) and when holding Ultra Necrozium Z and using Photon Geyser transforms into Ultra Necrozma giving Ultra Necrozma a +1 to its highest stat. Still has Light that Burns the Sky! Ultra Necrozma´s ability combines Prism Armor and Neuroforce.
Dusk Mane Necrozma Base Stats
HP: 104
Atk: 150
Def: 232
Spatk: 20
Spdef: 155
Spd: 19
Ultra Necrozma Base Stats
HP: 110
Atk: 200
Def: 170
Spatk: 20
Spdef: 150
Spd: 130
Dawn Wings would be a specially built version of Dusk Mane and when it transformed would be a Specially built version of the Ultra Necrozma.
Solution: Dusk Mane Necrozma Ability: Full Metal Body + Prism Armor ( Shadow Shield instead Full Metal Body if Dawn Wings) and when holding Ultra Necrozium Z and using Photon Geyser transforms into Ultra Necrozma giving Ultra Necrozma a +1 to its highest stat. Still has Light that Burns the Sky! Ultra Necrozma´s ability combines Prism Armor and Neuroforce.
Dusk Mane Necrozma Base Stats
HP: 104
Atk: 150
Def: 232
Spatk: 20
Spdef: 155
Spd: 19
Ultra Necrozma Base Stats
HP: 110
Atk: 200
Def: 170
Spatk: 20
Spdef: 150
Spd: 130
Dawn Wings would be a specially built version of Dusk Mane and when it transformed would be a Specially built version of the Ultra Necrozma.