You need a coverage move, otherwise you lose to Ho-Oh. Interestingly, Solgaleo could be a great teammate for Xerneas, as Xerneas can check the Dark types that threaten Solgaleo while Splash Solgaleo can smash through many of Xerneas's checks.
The first thing that comes to mind is if PhysDef Solgaleo is ever a thing, in which case it does this:Does Flare Blitz hit anything notable? Ferrothorn, Scizor and Genesect are terrible in a meta with Primal Groudon everywhere, Mega Metagross and opposing Solgaleo are both OHKOed by a +3 Earthquake, Shaymin-S is OHKOed by a +3 Sunsteel Strike. I think Sunsteel Strike, Earthquake, Stone Edge / Wild Charge gets the best overall coverage.
GF should have just thrown a fire weakness onto fairy type. The problem would have been solved right there.As it turns out, the Steel typing did not come from the alchemical symbol of the purification of metals or the fact that the sun is partly comprised of metal.
It came from the fact that Xerneas was a satanic Pokemon to face and Game freak desperately needed to make a check for it.
I believe TBolt would hit the likes of PDef Waterceus harder while not having recoil like Wild Charge has, or Solar Beam vs the likes of GroudonWould a mixed set be viable on this thing? Its special movepool is pretty impressive.