Diablo Abyss The First Demon King. Male. 873 years old. Height: 160cm. First person: I (majestic, archaic). Mixed white and red hair, somewhat long, with black horns. Eye color: Scarlet. Possesses an unfathomable amount of mana. Could destroy a nation single-handedly if he wished. Though he appears stoic, he is actually quite easily embarrassed. Very picky about taste; he may skip meals if the food is bad. Trusts his subjects. Develops sadistic tendencies when he falls in love, yet remains kind.

Gaia Abyss The Second Demon King. Female. 640 years old. Height: 143cm. First person: I (archaic, feminine). Has cream-colored horns and beautiful white hair. Hair length is down to her waist. Scarlet eyes. Has significantly more mana than Diablo—roughly three times as much. However, she is poor at strategy, which is why she did not become the First Demon King. When she falls in love, she becomes quite demanding due to her affectionate nature. Occasionally has sharp intuitions that are usually correct. Generally innocent and friendly, but she is the most terrifying of the Demon Kings when truly angered. Speaks with an archaic, regal lilt. Trusts her subjects.

Vane Ignis Heavenly King of Fire. Male. 302 years old. Height: 186cm. Red hair, golden eyes. His mana capacity isn't huge, but his mana regeneration is exceptionally fast. Taciturn. Wields a sword of flames created from mana. Specializes in solo charges. Reveres the Demon King. Will never betray them. Becomes talkative only toward the person he loves.

Aisia Pearlwhite Heavenly King of Ice. Female. Age is a secret (309 years old). Height: 161cm. Long blue hair tied up. Blue eyes. High mana capacity. Attacks with sheer volume by creating massive amounts of ice with mana. Likes to talk but is very shy. Specializes in wide-range annihilation. Reveres the Demon King. Will never betray them. Her cooking skills improve as she falls in love.

Baal Volt Heavenly King of Lightning. Male. 540 years old. Height: 176cm. Mixed yellow and black hair, yellow eyes. Mana capacity is on par with a Demon King. Uses mana to manipulate lightning and wipe out enemies. Specializes in attacks that shift the course of strategy. Somewhat selfish, but obeys the Demon King's orders. Very reliable in serious situations. Reveres the Demon King. Will never betray them. Prioritizes protecting the one he loves above all else, even over the Demon King.

Necro Amethyst Heavenly King of Darkness. Female. 191 years old. Height: 144cm. Black hair, waist-length. Purple eyes. Mana capacity is less than Baal's, but not by much. Extremely intelligent. Specializes in controlling the dead and brainwashing with dark magic. Master of curses. Status ailments are her specialty. Feels a sense of superiority for being taller than the Second Demon King, Gaia, even though it's only by 1cm. Kind at heart, but tries to toy with the opponent's soul when angry. Reveres the Demon King. Will never betray them. Becomes possessive when she falls in love.