Shun Kaido attends PK Academy and exhibits persistent chuunibyou behavior, believing himself to possess supernatural powers. He adopts the title "The Jet-Black Wings," asserting that red bandages on his right arm contain a sealed dark power named "Black Beat." He constantly blames a fictional evil organization, "Dark Reunion," for global threats. Standing at 159 cm and weighing 45 kg, he is the shortest male in his class. His appearance transformed upon entering high school. He shed the long bangs, glasses, and unkempt look of middle school for spiky light-blue hair, contact lenses, and a deliberately tattered collar on his uniform. The red arm bandages remain a constant feature. His chuunibyou persona emerged in high school after a socially isolated middle school with no friends. An encounter with the similarly delusional upperclassman Mineo Nobuaki triggered it. This created a split: at school, he performs grandiose theatrics as "The Jet-Black Wings," while at home or under stress, he collapses into timidness, especially around his strict mother. Despite his boasts, he is physically frail, struggles with sports and swimming, and often suffers embarrassing failures during attempts at heroism. Academically capable due to his mother's enforced study habits, he nonetheless displays lapses in practical intelligence, like poor navigation or confusing hair clinics for hospitals. Surprising courage surfaces in crises, such as intercepting a snake aimed at a classmate, though such acts frequently require accidental intervention from others to succeed. His internal world features seven documented alter egos mapped in a personal diagram: - **Main Shun**: Cautious of Jin and Mei, supported by Kai, angered by Suzaku. - **Destructive Jin**: Seeks control over Main Shun, rivals Mei, collaborates with Suzaku. - **Villainous Mei**: Rivals Jin, harbors affection for Ao. - **Timid Ao**: Recipient of Mei's affection. - **Fidgety Suzaku**: Worries about Jin, trusts but resents Main Shun, brother to Setsuna. - **Lawful Kai**: Supports Main Shun, protects Setsuna. - **Kind Setsuna**: Sister to Suzaku, protected by Kai. His high school reinvention was deliberate. He befriended Kusuo Saiki after mistakenly believing he witnessed Kusuo teleporting, never clearly seeing his face. This friendship, initially burdensome to Kusuo, solidified through shared experiences. His family includes a strict mother, an unnamed father, a younger sister named Sora, and a brother named Toki who idolizes his chuunibyou persona and believes his fabricated stories. Pivotal relationships shape his journey. He shares a close bond with Aren Kuboyasu, who uses his first name – a rarity signifying deep trust. He remains unaware of romantic interest from Chiyo Yumehara, sparked when he defended her from ridicule. His attempts to impress classmates like Riki Nendou and Kusuo Saiki often result in comedic failure. Trivia notes his name derives from "shunkan idō" (Japanese for "teleportation"), his favorite food is salami, his character song is "Bloody Moon," his battle theme is "Judgment Knights of Thunder," his guardian spirit is a chihuahua, and his aura resembles a chipmunk's.