An anime television series adaptation by David Production debuted on July 8, 2018. An anime television series adaptation was announced in January 2018. It is directed by Kenichi Suzuki and animated by David Production, with scripts written by Suzuki and Yūko Kakihara, character designs by Takahiko Yoshida and music by Kenichirō Suehiro. The anime series premiered on July 8, 2018 on Tokyo MX and other channels. The series ran for 13 episodes. Aniplex of America have licensed the series in North America, who simulcasted it on Crunchyroll. The series was simulcast in Australia and New Zealand on AnimeLab. MVM Entertainment acquired the series for distribution in the United Kingdom and Ireland. The opening theme is “Mission! Ken – Kō – Dai – Ichi” by Kana Hanazawa, Tomoaki Maeno, Daisuke Ono and Kikuko Inoue, while the ending theme is “CheerS” by ClariS.
- Erythrocyte (AE3803) / Red Blood Cell
- A red blood cell who has just started her job, delivering oxygen, carbon dioxide and different nutrients all over the body. She meets Neutrophil when he saves her from an attacking pneumococcus bacterium. She is clumsy and gets lost often, but determined to perform to the best of her ability. It is later revealed that she had encountered Neutrophil when they were younger, after he saved her from a bacterium.
- Neutrophil / White Blood Cell
- A type of white blood cell, whose job is to kill pathogens infecting the body. Despite his ruthless occupation, he’s actually quite soft-spoken and gentle. When he was still in school as a young cell, he saved AE3803 from a bacterium after she got lost in a training exercise.
- A type of white blood cell. She and her kind appear as lovely maids in big dresses, armed with a variety of large weapons to fight various invasive pathogens, and are often shown smiling cheerfully even in the middle of combat. While inside blood vessels, she and her kind take on the role of monocytes, and wear hazmat suits over their dresses.
- Killer T Cell
- A type of white blood cell that recognizes and kills various foreign matter and unhealthy cells. He is aggressive, pompous and rowdy, brutally taking pleasure in slaughtering pathogens and unhealthy cells. He especially looks down on white blood cells forming various relationships with non-white blood cells, like Neutrophil’s close friendship with Red Blood Cell. He is the sergeant of the Killer T Cells and is a harsh teacher to his students, the Naive T Cells. He has negative relationships with Helper T Cell and NK Cell, the former being his superior in the Killer T Division. In his youth, he was considered to be weak like the rest of the young T Cells, being only able to survive and complete training through the help of Helper T Cell, which at least made him stronger.
- A type of cell responsible for reconstructing the body from various injuries. They are depicted as cute children, due to their small cell size and act as construction and repair crew within the body. One platelet serves as their leader and she is most prominently featured in the show.
- Helper T Cell
- A type of T Cell that determines strategy and courses of action for dealing with foreign invaders. He is the main commander of the Killer T Cells and has an intellectual and smooth disposition, putting him at big odds with the rough and tough Killer T Cell, despite having underwent T Cell training together with him.
- Regulatory T Cell
- A type of T Cell that mediates and regulates the correct function and magnitude of immunological responses. She usually acts as Helper T Cell’s secretary, though she is capable of fighting when necessary. She went through T Cell training alongside Killer T Cell and Helper T Cell.