Got MasterBall with this. Your Giratina just attack faster than all of them lame decks that splash it and Mewtwo wins any game after Giratina goes down with a Red. The only bad match-ups are Darkrai/Weavile and Clodsire. Didn't play one mirror in almost 200 games somehow, I guess everyone thinks Mewtwo sucks. Just realized I made a mistake in the deck list, it's the attacking ralts and not the teleporting one.
>>57662660looks fun, cant imagine it being bad. Maybe you use baby arceus though so they have to take 3 knock outs? youre also going to need red. id consider cutting the 2 x speed and 1 erika for 2 red and 1 leaf since all of your pokemon have very low retreat costs other than arceus, he's the only one youd ever need ot retreat anyhow