Hey, I'm planning on having either of these two characters be referee for the second match:
I'm going to leave it up to the fighters which one they want. Personality-wise, Isaac is pretty level-headed but a bit irritable and maybe slightly snarky and/or immature. Proto is more level-headed than Isaac, kind of innocent, and maybe somewhat indecisive.
Also, since I might be interested in using whichever character doesn't become ref as a fighter in a future match, I'll go ahead and list their abilities:
Isaac:
Abilities: a shapeshifter who can stretch and contort his body in extreme ways, sprout wings, or even turn into a different animal. His body is very resilient.
Weaknesses: not used to fighting, easily caught off-guard, no weapons or real offensive capability except his claws and teeth
Proto:
Abilities: a witch who can cast spells and stuff (no specific kind; she actually doesn't do magic that much in my comic). Very athletic.
Weaknesses: a bit too kind-hearted to hurt people easily, not used to fighting, can't do much magic without her wand