For me it would be Murky.
This is a game where the most powerful Heroes and Villians from multiple universes battle. You got world shaking dragons, leaders of entire space Empires, mages with unbelievable magic powers, demons and angels battle for control of all reality. Oh yeah, there is also a baby fish person. A baby fish person who’s weapon is … an actual fish. I mean really? He hits enemies with a fish. That’s on par power level with arch-angels, ancient world shattering dragons, and the leaders of species who have space travel who’s Empires span dozens of worlds. Very even.
If Murky and an enemy trade takedowns Murky only counts as 1/4 of a takedown, and he will respawn faster and be back in the fight before his enemy. He can ignore the 1st obj on most maps and cause as much or more damage as that 1st obj will cause.
So yeah, many annoying characters in this game, but Murky stands out as number 1 too me.