[@Bartimaeus]
The difference in intelligence would be his biggest downfall. He may, with a bit of time, outstrip either of them in strength. But Fury and Kanitah aren't dumb by any stretch, they're very well trained warriors. Capable of fighting equally strong or stronger foes. The deciding factor is their intelligence, they'd beat him down by outsmarting him.

At least that's my point of view.

Even worse, I have two characters who would negate his Contagious Rage ability entirely.

One who feeds off of anger, and the other who is literally the angriest person in my universe.