Make Xerneas Modest over Timid
It will need the extra power.
Do not under any circumstance run mixed Mmy. It's just plain bad. You should opt for a CM or Taunt set
Mewtwo @ Mewtwonite Y
Ability: Pressure
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Psystrike
- Calm Mind / Taunt
- Fire Blast / Focus Blast
- Focus Blast / Ice beam
Mixed Rayquaza is good, but the set you're running is a little sad. Unless you're in a 1 vs 1 metagame, you should never run Hyper Beam on a Pokemon. It's not even bad. It's more than bad. Horrible doesn't even cut it. Even Sunkern can't approve of it.
The flying type is an offensively great type. Whether majority of the tier is weak against it or not, since it will nuke everything that isn't a steel, electric or rock type, and even then it can break through certain things if the STAB move and the user of the move has divine offensive pressure, which Rayquaza has. But seriously, Air Slash won't be scratching any fly in Ubers, so just....no
If you however do wish to run Mixed Rayquaza, just use the standard set, which would be:
Rayquaza @ Life Orb
EVs: 4 Atk / 252 SpA / 252 Spe
Hasty Nature
- Draco Meteor
- V-create
- Extreme Speed
- Dragon Claw / Earthquake
You could run Earthquake to deal with Pokemon such as Dialga and Heatran, but Dragon Claw's power is much needed as a mixed Pokemon is meant to be able o deal with Pokemon of both defenses, and V-create can't do it alone, as it enables Pokemon such as Ho-oh to simply wall this set, and Ho-oh is one of those Pokemon you don't want to be walled by. Trust me.
You could also opt for a Naive nature if you want to attempt living priority, but it honestly really does not matter since Rayquaza will be equally useless after getting hit by powerful priorities and Ice shard is never seen in Ubers, so yeah
You don't exactly need a Double Scarf as it actually really want help this team much. Seeing as Ekiller Arceus basically just steamrolls your team, I would suggest running a physically defensive Yveltal set. The set will enable you to survive a +2 Jolly LO Extreme Speed at full health and kill it or at least make it as good as death fodder after one powerful STAB Dark Aura boosted Foul Play. You could also opt for a physically defensive support Groudon to soft-check Extreme Killer and run LO Yveltal, but I think that would be a little less effective in your case.
I didn't exactly help your team much, just optimized the spreads, main reason being, the sole way of saving this team from Eternal Damnation is by completely changing it, which would unfortunately break the rules of rmt, and tbh, even if I got your permission to do it, I still wouldn't because I don't see how that would better teambuilding skills. The whole Hoenn trio legend thing is cute and all, but really not as effective as people make themselves believe. Seeing as rn Geomancy Xerneas really just destroys everything on your team, as it can set-up on everything bar Kyogre and KO everything else in return. Saddest bit would be that every variant of geoxern, whether it being Mixed Geoxern, Aromatherapy Geoxern or Substitute Geoxern will destroy your team with just Moonblast, thus not even needing coverage. In fact, every variant of Xerneas can be a great threat to your team, making me suggest that while revising your team, which is something I would recommend if you do want to better it, you should consider dumping one or 2 of the Hoenn legends, ro anything else on your team for that matter, and try fitting in a decent Xerneas check or counter such as Mega Mawile, Aegislash, Scizor / Scizor Mega, Arceus-Fire and all those good stuff, as checking Xerneas is the first step at surviving in a metagame / banlist, call it whatever you want, such as Ubers.
Might be a little blunt, but always remember, I do it #BecauseIcare o3o!
