"What do you mean I look cute?"
Jubei is generally agreeable, sociable and optimistic. Whenever there is a great threat such as Ragna or the NOL around, he always keeps his laid-back attitude and stays relaxed. He makes the best of every situation and is always trying to see the good in everything.
Jubei is one of the Six Heroes, Ragna's master, and Kokonoe's father. He battled the Black Beast alongside Hakumen, and played a part in the Ikaruga Civil War. The Kaka Clan were genetically engineered from his DNA. Despite his appearance (he is considerably short and does not come off as threatening, resembling a cat more than either of his descendants), he is a powerful warrior, with numerous people referring to him as the strongest being on the planet. He works to safeguard his friends in their times of need. Before the start of the series, his partner Nine was murdered by Yūki Terumi. Jubei seems to have an awkward relationship with his daughter, though the reason why is currently unknown.
Alongside his moniker as the strongest being on the planet, Jubei is sometimes referred to as the Mitsuyoshi.