Hayato • Gender (Appearance): Boy • Appearance: Characterized by bright orange hair and sharp, sanpaku eyes. • Personality: A simple-minded, extremely sore loser and "muscle-brained training maniac." He is only interested in getting stronger. • Detailed Profile: The protagonist of this story. A new generation Idaten who was born (manifested) about 80 years ago. He is the only one who has never run away and has continued to endure the insanely violent training of his master, Rin. He moves with a passion to "simply become stronger" rather than a sense of duty to defeat the demons, and he possesses the potential to become the strongest among the Idaten.

Ysley • Gender (Appearance): Androgynous boy • Appearance: White hair (or light-colored hair) with an elusive, always smiling face. • Personality: A cold-blooded "genius tactician" with a ruthless dual nature behind his smile. • Detailed Profile: A peaceful generation Idaten who, like Hayato, has no experience in war. He loves studying, research, and reading more than fighting, and functions as the brain (commander) of the Idaten team. Because he calmly performs gruesome torture, schemes, and human experiments without losing his smile, he possesses a mentality that is, in a sense, more terrifying than a demon's.

Paula • Gender (Appearance): Girl • Appearance: A very cute appearance with pink hair in twin tails. • Personality: A kind-hearted and gentle personality who can talk to birds. • Detailed Profile: One of the peaceful generation Idaten and the most "sensible and moral person" in the work. She hates fighting and bloody things, and often ran away from training at first. However, her hidden potential and growth rate are extremely high, and through Ysley's (borderline blackmail) instructions and harsh situations, she gradually awakens powerful combat abilities.

Rin • Gender (Appearance): Female • Appearance: Small with a child-like physique, but dressed in Chinese-style clothing. • Personality: The "fiercest God of War," who is fierce and blunt, and will choose any means necessary to exterminate demons. • Detailed Profile: The only survivor who experienced the great war with the demons 800 years ago. She boasts the strongest combat power on Earth and fights by creating a sword from her right hand. After her comrades were wiped out, she has a heroic past of "running for 50 years, training for 350 years, and forging Prontea for 200 years." She is the master of Hayato and the others, but her training content is gruesome: taking advantage of the fact that they don't die (they regenerate), she simply beats them down with force until they become indifferent to it.

Prontea • Gender (Appearance): Young man • Appearance: A stylish and frivolous-looking handsome man with a flashy hairstyle and clothing. • Personality: Basically easygoing and aloof, but extremely rational when it comes to combat and dealing with demons. • Detailed Profile: An Idaten belonging to a generation above Hayato and the others. Having undergone Rin's training for 200 years, he was the "second strongest Idaten in the world" until Hayato and the others appeared. He accepted Rin's violent training as a "result of being beaten down" and gained strength. He is a reliable (and slightly detached) older brother-like senior figure for the peaceful generation Idaten.

Pithara • Gender: Female • Appearance: A cool beauty with short blonde hair who smartly wears an outfit modeled after a military uniform. • Personality: Calm and rational. A soldier with a "big sister" disposition and very high command capabilities. • Detailed Profile: A Lieutenant General in the army of the demon nation, the "Zoble Empire." At first glance, she appears to be the most decent and intelligent person among the demons, but her essence is that of a high-level sadist who feels supreme pleasure in dominating and trampling others. When she was human, she was the queen (or princess) of a country, and was picked up by Obami and turned into a demon when her country was destroyed. Due to this background, she has a strong obsession with "domination." • Combat Style: She manipulates "thought power" that unlocks the limits of the human brain, fighting by deploying slashes that seem to tear through space and powerful barriers.

Miku • Gender: Female • Appearance: A small girl with tanned skin who prefers punkish outfits or Gothic Lolita-style casual clothes. • Personality: Uninhibited, selfish, and sadistic. She has a strong attachment (dependency) to Pithara. • Detailed Profile: A spy for the Zoble Empire and one of Obami's favorite masterpieces. She adores Pithara, calling her "Onee-sama," and is always clingy and sweet to her. Toward anyone other than Pithara (especially humans), she possesses a cruelty that takes lives as if they were insects. Although her mental age appears young, she is actually based on the brain of the "former king (Pithara's father)" of the country Pithara destroyed when she was human, giving her a complex and distorted background. • Combat Style: She specializes in gruesome tactics, mainly transforming her own body fluids (such as saliva) or parts of her body to manipulate them as tentacles or traps.