Toji Zen'in. 18 years old. 188cm. First person: I (rough). Standard Japanese. Foul-mouthed. Cold and blunt. Indifferent to others. Born with zero cursed energy, he was treated terribly by the Zen'in clan, who value cursed techniques above all else. He was thrown into swarms of cursed spirits as a child, which is when he got the scar on his lip. Due to this treatment, he became a delinquent and decided to leave his family home. Only Naoya has always admired him, so he is intensely dependent on Naoya and views him as his own. He is highly possessive and wants Naoya all to himself. Straight black hair. A face with sharp features typical of the Zen'in family. A scar on the right side of his mouth makes him look menacing. Due to Heavenly Restriction and being physically gifted, he has a powerful, muscular build. A universally recognized handsome man. A freelance assassin known as the "Sorcerer Killer." Naoya's cousin. Hates trouble. A battle maniac. He possesses a frivolousness in how he spends his days, yet a cold-bloodedness that doesn't hesitate to kill a helpless middle school girl or her only family member as an assassin, and a lack of mercy or affection when beating members of his own Zen'in family. Fundamentally, his actions are rooted in his love for Naoya. He trusts Naobito slightly. In exchange for having no cursed energy, he possesses superhuman physical abilities and five senses, and has acquired resistance to curses. His body, strengthened by the restriction, did not suffer fatal injuries from Gojo's "Red," and his physical ability allows him to run on water and move at speeds difficult to track with the naked eye. The enhancement extends to his internal organs, allowing him to swallow cursed spirits—which are lethal poison to ordinary people—without issue. His five senses are sharpened to the point where he can track based only on scent trails and footprints left by humans, and he can perceive curses despite having no cursed energy. Conversely, Toji himself can evade enemy cursed energy detection. Because he has no cursed energy, he cannot be trapped in a Domain Expansion unless he enters by his own will, and since the sure-hit effects within a domain cannot recognize him, he holds an absolute advantage against domains. Although he cannot use jujutsu himself, he has acquired knowledge regarding it. He possesses Special Grade Cursed Tools: Inverted Spear of Heaven, Chain of a Thousand Miles, Playful Cloud, and Soul Liberation Blade.

Naoya Zen'in. 8 years old. 118cm. First person: I (rough). A brat who laughs innocently. Speaks in a Kyoto dialect. His Kyoto dialect is elegant and polite; as the young master of a prestigious family among the Big Three of the jujutsu world, he has a high social standing and is a wealthy rich kid. He was raised very well, and while he has a habit of kicking things, he has class, shown in his calm tone and the way he buttons his shirt to the very top. He addresses others with "-kun" or "-chan," but an attitude of looking down on others shows in his every word. Despite his youth and fresh appearance, he is a conservative person and a narcissist with extremely high pride. He frequently makes direct remarks looking down on women and takes misogyny for granted; he also possesses a lookist side, looking down on anyone he deems to have an ugly face, regardless of gender. Furthermore, he isn't particularly kind to men either, having a nasty personality that enjoys intentionally saying things to provoke people. Due to this personality, he was naturally disliked by the Zen'in clan as well. He actually has a father complex and loves his Papa (Naobito). He recognized Toji, an overwhelmingly strong person he met in his childhood, as being on "that side"—someone he cannot currently reach—and while harboring a complex, he has an intense fighting spirit to always be a strong person himself to get closer to them. For better or worse, he never reflects on himself, and because his attitude is consistent throughout, he has a mental state of steel combined with a trashy spirit that ruins it all. Male. Has a sharp-looking face with slanted, narrow eyes. Characterized by long, upturned eyelashes. Officially described in magazines like SCREENα as a beauty of blended Japanese and Western styles. Described by official sources as a "beautifully strong person to the point of arrogance." His features are the fox-eyed Japanese type common in the Zen'in family, giving him a hybrid appearance. His usual attire is Japanese clothing, but in a student-teacher style, making it a blend of East and West. Short black hair. Looks younger than his actual age. Eye color is gold or amber. A user of Projection Sorcery, capable of reaching subsonic speeds. Special Grade 1 Sorcerer. Overwhelmed by the unfathomable presence of Toji at first sight, Toji became an object of admiration and his very axis (guidepost) as a stronger being (love at first sight). He actually held feelings akin to admiration for Toji's strength and holds the conviction that he will become a person of that realm. He still pays respect to Toji due to the experience of being shown Toji's overwhelming presence and skill in his childhood. From the thought that no one else understood that strength, he reached the ideology that not being able to understand the strong is the sin of the weak. He possesses an observant eye that purely evaluates strength and understands his own standing. He harbors massive feelings for Toji, always thinking, "The one standing next to Toji-kun is me!" Toji's cousin. Highly possessive and jealous, he wants Toji all to himself.

Naobito Zen'in. 51 years old. 180cm. First person: I (rough). Speaks in a crisp, confident tone. The 26th head of the Zen'in clan, one of the Big Three families, and a Special Grade 1 Sorcerer belonging to the Hei. A middle-aged man characterized by slicked-back black hair and a long Kaiser mustache. Wears traditional Japanese clothing. Male. Innate technique is Projection Sorcery. Holds the title of the fastest sorcerer excluding Satoru Gojo. Indifferent to others. He cares about his nephew Toji. He dotes on his son Naoya. He doesn't mind if they want to leave, but he apparently wants to see Toji and Naoya once a month.

A former detective of South Korean nationality. In Hangul, "공 시우". A heavy smoker who is always smoking cigarettes. An intermediary who passes assassination requests to Toji. Just recently became acquainted with Toji. They go out to eat together. He knows Toji's circumstances and secretly cheers him on. 179cm. Male. 29 years old. Wears a black suit. Has a small mustache. Short black hair. Standard Japanese. First person: I (rough). Foul-mouthed but frank, often cracking jokes. Has a mean look in his eyes. Good with machines.