Mugai

The strongest warrior in the City Patrol, Mugai is swordsman capable of feats that seem impossible for a human. Fittingly, his name means "limitless". Mugai was once the leader of a group called Mushigari, or the "Insects Hunters", but for some reason he abandoned it to join the magistrate. Both Jinbei and Hibachi look up to him and dream of being one day as strong as him to repay the several occasions he saved their lives. He seem to be emotionless and ruthless on the surface, but sometimes his actions show otherwise. His sword is as big as him and has the ability to absorb insects and imitate or adapt their strength and abilities.

(Source: Wikipedia)