The main protagonist of this story, Jio is a boy with great battle skill, great trust towards his friends and an ability to persevere, but he also has an obsession with money and is not soon to show his feelings, often hiding them or blaming other factors.
His dream is world domination, which other people often laugh at, calling it a child's dream until they see his abilities.
Jio started his life without friends, the people in his village forcing him to leave after the death of his only friend Jin's parents for which he was blamed. He was later trained in the wild by a wolf, known as Zero. However, after completing his training he was chased away again, giving him a chance to complete his dream.
His third friend, came in the form of Ruby Crescent, a girl in search of her father. At first, he helps her as a paid bodyguard, but leaves once she runs out of money. She ends up fighting a man claiming to be Satan, but the real Satan (sealed inside of Jio) easily beats him once Jio is knocked out. Once Jio is conscious again, he says he will follow her until she can pay him for saving her. He claims (in front of her) that he is only her bodyguard and nothing more, but Jio sees Ruby as a precious friend and even seems to have a crush on her.
After having Ruby for a friend, Jio grows out to be more trustful, and slowly breaks away from his dream of world domination choosing to be more helpful and caring of others, quickly gaining more friends and meeting Mr. Wick and Mrs. Basil, which he sees as his father and mother (never having known his real parents). They were murdered by Kujaku, one of the Four Guardians of Zenom Organization.