Starting with the team, it does need a good defogger. Yveltal can do it, but it's better for defensive sets, not offensive. Go for Arceus-Fairy. Draco Meteor is unnecessary. So replace that. You need a better Dynamax Yveltal and Calyrex-S check, that isn't Yveltal, since Draining Kiss OHKOes after Rocks and a Nasty Plot. Go for Mega Tyranitar, replace with Mega Rayquaza. Your team is too hyper Offense, needs some balance. T-Tar is able to check both non-Earthquake Mega-Rayquaza, and non-Focus Blast Yveltal, which are uncommon, making it easy. Also, Calyrex can't ever beat T-Tar, and trying to escape means its dead to Pursuit. Do give Max Sp. Def on it, so that Max Overgrowth deals 30% unboosted. Adding Thunder Wave and Rock Tomb makes it no lure for set-up, while Crunch finishes Dynamaxed Calyrex in one go. Assault Vest is unnecessary, it doesn't protect it from getting OHKOed by Special ghost and dark type moves. Giga Drain inferior to Leaf Storm, but get rid of that set and have a Ghostium Z, OHKOes Primal Groudon, M-Ray, Crowned, etc then lure them to bring Ditto, which is annihilated by Pursuit :3 My fav set. Also, try a mixed set on Primal Groudon, along with Rock Polish. Do note that if running mixed means you have to go -Sp.Def nature, which weakens you against Primal Kyogre, meaning you're two OHKOed by Ice Beam, but -Def nature means two OHKOed by Close Combat by Zacian Crowned though. You do not have a Stealth Rock setter, so take Primal Groudon as one. Unlike what the other answer says, having Wild Charge on Zacian-Crowned allows to beat Arceus-Water and Ho-Oh much better than Play Rough. Also, what the other answer says about HP EVs on Yveltal doesn't make sense, since all pro players use 252 Spe on life orb sets, and also as Smogon recommends. Also, Extreme Killer is definitely not a good go, due to how offensive the team is, and lacks on defense. You should try the Calm Mind set, with Arceus-Fairy.
Arceus-Fairy @ Pixie Plate
Ability: Multitype
EVs: 248 HP / 172 SpD / 88 Spe
Calm Nature
- Judgment
- Recover
- Will-O-Wisp/Calm Mind
- Defog
It's your choice to Will-O-Wisp Dusk Mane and Zacian-C or to set-up with Calm Mind. Don't be afraid of Ditto, due fact that it Recover with Calm Mind unlike Ditto who is locked due to Choice Scarf. Also, Sp.Def Arceus-Fairy doesn't synergies well with Tyranitar, since both check same things. You can try Lugia, but if you don't want a worsened matchup against Calyrex at the risk of getting weakened to Primals, you can try Ho-Oh. Hope this helps.
Edited team: https://pokepast.es/183793f82e717f13
