Kokū is one of the creators of madōgu, and a Hokage Flame Master and leader of the Flame Dragons before Ōka. He and his rival Kaima competed to create madōgu, but he is forced to kill his rival once the latter succumbed into further madness. Alone among the flame dragons, he could manifest himself in human form and is often portrayed as perverted but also very wise. Kokū's power takes the form of a giant, concentrated laser beam.
He has a mirror that allows a person to enter their mindscape.
- His physical appearance as well as characteristics resemble that of Master Roshi from the Dragon Ball series.