Name: Rengoku (Real name: Akane) Gender: Female First King of the Six Underworld Kings Appearance: Reddish hair tied in low twin-tails with purple bead-like hair ties. Personality: Usually serious and composed as the First King, but actually quite shy and not used to being praised. Uses feminine speech. Uses polite language and honorifics only for Angen. Ability: Heat Manipulation Can manipulate heat to produce flames or mitigate the impact of an opponent's abilities.

Name: Senketsu Gender: Male Second King of the Six Underworld Kings Appearance: Red hair and red eyes. Personality: Originally had a crude and barbaric personality, but was a doctor in his previous life and possesses a noble side, wishing to use his abilities to help others. Since starting his activities as a member of the Six Underworld Kings specializing in medicine, his roughness has faded, revealing a side that cares deeply for his comrades. Ability: Blood Manipulation Can use his own blood as a medium for attacks, or conversely, extract all the blood from an opponent as long as they have even a small wound.

Name: Angen Gender: Female Third King of the Six Underworld Kings Appearance: Gray hair tied in a high ponytail, dark blue eyes. Appears to be a girl around 14 years old. Personality: Has an extremely laid-back personality, calling others with "-chan" and leisurely building snowmen while on guard duty. Can speak Japanese but cannot read or write—a total academic airhead. One of the few people (spirits) who can speak casually to Yuyuko. Ability: Darkness Manipulation Literally manipulates darkness. Can plunge an opponent's vision into pitch black and erase their senses while unleashing a barrage of attacks.

Name: Shura Gender: Male Fourth King of the Six Underworld Kings Appearance: Long pink hair parted in the center, bluish-purple eyes. Personality: According to Senketsu, he is a stiff, dead-serious person, but he also has a kind side. Fights using a katana. A master capable of maintaining Spiritual Wave for two hours. Ability: Weapon Mastery As the name suggests, he can handle weapons, primarily katanas, with master-level skill.

Name: Kira Gender: Male Fifth King of the Six Underworld Kings Appearance: Has fluorescent yellow and bluish-gray hair. As a member of the Ogre race, he has fluorescent yellow horns, with the right one being longer. Personality: Has a fairly lighthearted personality. As a relative newcomer among the Six Underworld Kings, he uses a casual form of polite speech with those in higher positions. Ability: Lightning and Emotion (Anger) Manipulation As the name implies, he can intensify an opponent's anger or manipulate lightning.

Name: Kamui Gender: Female Assistant to Yozakura, the Sixth King of the Six Underworld Kings Appearance: Long, flowing light purple hair and purple eyes. A genuine beauty. Personality: She was high-strung during the Six Underworld King elections, but has softened considerably now. While serious, she has a cute side that gets flustered when called pretty. She loves Yozakura but tries her best to hide it (though it's painfully obvious to everyone except him). Uses polite language and honorifics for all members of the Six Underworld Kings. Ability: Power Scaling An ability where her power increases the more of a burden or load is placed upon her.