Main characters ; : :A third-year high school student and later university student who is a fan of the in-universe manga
Isobeyan. She is of average height, has short black hair, and wears red glasses. Kadode has been best friends with Ouran since she was ten years old and calls her "Ontan". Despite her father, Nobuo, going missing on 8/31 and her friend Kiho dying in an incident involving an invader spacecraft, she has little interest in politics or the invaders. ; : :A third-year high school student and later university student who is Kadode's best friend, she has oval-shaped eyebrows, is often seen drooling, and has long, black hair that she wears in pigtails with skull-shaped clips. Although Ouran is eccentric, friendly, and expressive in public, she tends to show her true self only to her friends and family. Ouran enjoys video games and dreams of bringing about the downfall of society and enslaving the human race. She values her friendship with Kadode above all else, calling their bond "absolute".
Supporting characters ; : :A fellow student at Kadode's and Ouran's high school who is also friends with Ai and Rin. She is short, sports a bob haircut, and has very thick eyebrows. As the most recent girl to join their friend group, she sometimes feels left out amongst the other girls. Her boyfriend is Kenichi Kohiruimaki. During the new year's holiday, she dies when an invader spacecraft is shot down over her apartment. ; : :She was a friend of Kadode and Ouran in high school and university. She is of short, round stature and has small eyes and oversized glasses. Ai cares very little about the cold war between humans and the invaders, investing most of her time into caring for her five younger brothers. Her best friend is Rin. ; : :A tall, lean, and angular girl who is a friend of Kadode and Ouran at high school and in university. Although she is almost always silent, Rin is noted to be a major fan of
boys' love manga. ; : :A young woman from
Hakui, Ishikawa, moves to Tokyo and attends the same university as Kadode, Ouran, Makoto, Rin, and Ai. She has distinctive pink blush marks and an oval-shaped nose. During orientation, she bonds with Kadode over their shared love of Isobeyan and joins her friend group. Futaba came to Tokyo in order to become involved in the "peacesquid" movement, which advocates for the safety and rights of invaders. ; : :A student at Kadode and Ouran's university who moved from Hakui along with Futaba. Although Makoto is a boy, he loves dressing in women's clothing and wearing a blond wig. He wanted to be seen as an idol, so he moved to Tokyo in order to escape small-town gender norms and found an accepting group of friends in Futaba, Ouran, Kadode, Rin, Ai, and Oba. ; : :A teen idol who disappeared on 8/31 and whose body was possessed by an invader. Oba befriends Kadode and Ouran, who quickly learn that he is an invader impersonating a human. ; : :Kiho's anxious and
terminally online boyfriend. Kenichi is radicalized following the death of his girlfriend and forms a
vigilante group intent on killing off the invaders. ; : :Kadode and Ouran's high school teacher, who has a stoic and pessimistic demeanor, after their graduation, Kadode pursues a brief romantic relationship with him. ; : :Ouran's older brother, who is obese but has idol-like features, is a
Hikikomori who spends his days moderating internet forums. ; : :Kadode's father, a manga editor, disappeared on 8/31. ; : :The titular character of the in-universe manga is
Isobeyan. A parody of
Doraemon, he is a humanoid mushroom who gives Debeko various gadgets in a misguided attempt to help her solve her problems. ; : :A parody of
Nobita Nobi in the in-universe manga
Isobeyan. She is a careless and unintelligent girl who uses Isobeyan's gadgets to solve her problems, which usually backfires. ;Head of the Invaders : ; : ; : ; : ; : ; : ==Media==