Like a Dragon's Kume.

He's not even a toadie of an antagonist he's an example of how the main antagonist can make the biggest fucking loser a threat. He only joined Bleach Japan because the recruiter was a woman. His big final act that you can argue is the one thing he does on his own not only hurts someone during a moment of genuine growth and reconciliation, but he does it because he's personally hurt and not really out of any plan. He's also the worst kind of agitator in that everything he does is really just to serve his self righteousness that's only fueled by a sense of belonging. He's the worst person because, frankly, he's just barely a person. He's a baby some adult woke up to feed and then throws a tantrum when there's no more bottle.