Saruta, Hiko

猿田彦

Harsh, cruel, brutal, and extremely powerful and skillful as a warrior. A real butcher. He killed every single person in the country of Hi (Fire) following an order from Himiko-sama. But after he met Nagi, something changed him. In the past, his clan was annihilated, and he is the only survivor. He has been taken to Yama Tai Koku.
His name consists of three kanji: 猿 monkey (saru), 田 rice field (ta), and 彦 boy (hiko - actually very old one). Maybe it means nothing, but it can help understand his personality in some way.