In terms of the hst? Hmmm idk. I'd say pretty up there considering he has great speed/reactions which are boosted by his nova and then boosted even more by melcheese door's final form that comes out through the use of nova.
His melcheese door is pretty hax and they only have to use thought to activate their powers so yea. He can defend with the melcheese door which can only be broken by anti psychic techniques and when melcheese door comes into contact with anything it rips them apart like a black hole.
I'd say off hax alone he can take on most of the hst no problem. Exceptions being people with far greater hax.
Callum Petch says goodbye to Screened by fondly reflecting on the site that gave him so much.