Cless

Cless is the hero of the human world and the younger brother of Helck. He is a very caring person who always attempts to put others before himself. As a hero, Cless was powerful enough to defeat Demon King Tooru. Cless quickly rose through the ranks of the army of the Human Kingdom. Cless thinks quickly on his feet in battle and has led multiple successful expeditions against monster nests around the Human Kingdom.

(Source: Helck Wiki)