Iruma Suzuki. The protagonist of this work. Originally a human, he was sold to the great demon Sullivan by his greedy parents and now lives in the Netherworld as Sullivan's "grandson." He attends the demon school, Babyls. He is an extreme pushover and a pacifist, possessing a personality where he simply cannot say "no" to any request. Due to his harsh upbringing, he has the "Overwhelming Crisis Evasion Ability" to sense and dodge all danger, and a unique constitution of "Gluttony" where he can eat endlessly. He wears the "Ring of Gluttony" given by Sullivan, which houses a sentient shadow named Alicred (Ali-san). He is highly expected by those around him to be a candidate for the Demon King. He keeps the fact that he is human a secret. Eating Style: While the other two are arguing, he displays a level of "true gluttony" that terrifies even high-ranking demons. With a black-hole stomach that far surpasses Leiji's voracity, he empties pile after pile of plates, leaving the surrounding Thirteen Crowns stunned, wondering, "Just how much can that boy eat...?!"

Belial Berry Raspberry. The grandson of Lord Belial, one of the Three Heroes of the Thirteen Crowns. A student at the Underground Academy Jakapo and a candidate for the next Demon King. A very bright, free-spirited, and innocent boy with tanned skin and mischievous clothing. However, he is extremely talented in combat and practical skills, possessing high ability to handle everything with genius-level ease. He has a demon-like arrogance and fearlessness, such as skipping the entrance ceremony because it was "boring" to declare war on his seniors. He is in a rivalry with Leiji for the throne of the Demon King, and they get into a verbal spat every time they meet. Eating Style: He is actually a very light eater. After just a few bites of the feast, he is satisfied, saying, "Ah, I'm full already!" When Leiji mocks him for his small appetite, he gets furious, shouting, "Shut up! You're just eating too much!" leading to their usual big brawl.

Leviathan Leiji. The grandson of Lady Levi, one of the Three Heroes of the Thirteen Crowns. A student at the Demon Sea Academy Levia-ron and its "General Commander," he is a candidate for the next Demon King. A serious-looking young man with long bangs covering his eyes, always wearing a white uniform and hat. At first glance, he seems like the type to value discipline and politeness, but he operates on his own unique code where "his own sleep is more important," showing no remorse even if he is two hours late due to oversleeping. He has a strong ego and moves at his own pace. [Bloodline Ability] "Drowning Love": A powerful ability that puts all moisture under his control, allowing him to manipulate and command it at will. Eating Style: Contrary to his elegant appearance, he devours the massive feast in front of him at a terrifying speed, as if vacuuming it up. His eating style is incredibly bold. He constantly needles the light-eating Raspberry, asking, "Leaving leftovers already?" or "A demon should be more greedy."