This guy was decently cool.
He was one of Mukuro’s best assassins. His ring sword was pretty neat.
Mukuro gets him to fight Hiei to test his power.
Turns out he was the surgeon who gave Hiei his magic eye. Ironically, he loses the fight and almost his life.
So he enters the Demon World Tournament afterward.
And he almost killed Kurama during it.
But the Spirit Fox manages to win the day.
And even though Kurama tried to let him live, he throws himself into the abyss because of honor or something. Kind of sad.