TV-Series
Description
Kōji Tongari, also known as Kouji Tongari, serves as a central character. Hailing from an affluent family, he possesses a private plane and a villa on the fictional Hyakujo Island for summer holidays. Raised with considerable wealth, he initially boasted about his family's status and acted cheekily.

He exhibits a profound attachment to his mother, described as an extreme "mama's boy," constantly seeking her permission and crying out for her when distressed. Academically gifted, he ranks at the top of his class and attends cram school late into the night. Despite his intelligence, he struggles with fears and anxieties, frequently crying when frightened and lacking confidence. He received a diagnosis of pseudomyopia during an eye test.

His personality undergoes significant evolution. Initially a lackey to the bully Butagorilla, he displayed hostility toward Kiteretsu and Korosuke, even participating in pranks against Korosuke like attempting to steal a temple fruit while disguised. Over time, he matures, transitioning into the straight man to Butagorilla's antics and forming genuine friendships with Kiteretsu and Korosuke. He joins their adventures, though Butagorilla's schemes sometimes exclude him from trips.

Beyond academics, he possesses multiple talents. Skilled in drawing, he won a local children's art contest and painted a mural in a public bathhouse. His manga abilities are notable; as a fifth-grader, he submitted work to the fictional Geragera Comic magazine, showcasing a style reminiscent of the series creator. He is adept with toys and gadgets, including video games and mini 4WDs. A feminine side emerges through his mother complex, yet he demonstrates social savvy, forming friendships with girls in cram school and other settings.

He copes with bullying from Butagorilla by secretly attending a boxing gym, using a punching bag to vent frustrations, a practice Korosuke later joins. However, after his mother and Butagorilla discover this, he quits boxing, lacking natural aptitude. Moments of overconfidence when using Kiteretsu's inventions often lead to failure, and his attempts to become more manly frequently backfire.

His dislikes include green peppers and tomato juice. An episode involving a "Past Life Detector" invention revealed he was a cockroach in a previous life, causing him shock. He also deals with childhood trauma, having been nicknamed "Pee-in-the-piss Ton-chan" in kindergarten due to lingering incontinence issues.

He has multiple girlfriends and shows romantic interest in a theater artist named Hanamaru Satsuki, whom he meets when she transfers to his school; his mother approves of this interest. He undertakes rebellious acts, running away to locations like Nagano Prefecture and Izu. In one episode, he rescues a stray cat that saved his life, gaining his mother's permission to keep it.

After graduating high school, he attends Takao University. His character design receives minor changes in later media, such as "New Kiteretsu Encyclopedia."