Real name:
樫井 栄児 Kashii Eiji
Fought his first battle when he was five, killing everyone else. Has wanted to be hailed as a genius ever since. The name of his saber is [Gobouken]. While the saber itself isn't very special - it's just a regular mass-produced item - he wields it with great care. Despite looking thin, he's quite the big eater. As a warrior, he does not consume alcohol. He knows exactly where to go when he wants to eat by himself.
Gobouken: 牛蒡剣, which contains 牛 (ox) and is a homonym of "bayonet."