User blog comment:Pistashio TV/Shadow vs Mewtwo - REMATCH!/@comment-36546683-20190306193739/@comment-27389401-20190320001808

By using scaling, the player can decide Mewtwo to battle Legendaries like Arceus and Creation Trio who can put up a fight against Super Shadow scaled to Solaris.

But you can have your decision if you're not using the Mewtwo who can fight the Pokémon gods.