Zeru

Zeru is the "Captain" Of Jolly Devil Six. His power is based around fire (火炎術), his only attacks he uses are Fire Aura, and a fire blast attack. He seemingly punches Hiei through the stomach, then shoots a fire blast at him, yet again seemingly killing him. Then Hiei appears behind Zeru, stunning him as he doesn't realize that a fire-based attack won't work on other fire demons. Thus he is killed by the infamous Black Dragon Hell Fire (Jao Ensatsu Koku Ryu Ha) (referred to as Dragon of the Darkness Flame in the English version). Upper C class demon.