- Shoya Chiba
- B Cell
- Natsumi Fujiwara
- Lactic Acid Bacteria (Panda)
- Kana Hanazawa
- Red Blood Cell (Erythrocite)
- Saori Hayami
- Regulatory T Cell
- Kikuko Inoue
- Macrophage
- Akira Ishida
- Cancer Cell
- Yûsuke Kobayashi
- Average Cell
- Yurika Kubo
- Lactic Acid Bacteria (Spotted)
- Tomoaki Maeno
- White Blood Cell (Neutrophil)
- Maria Naganawa
- Platelet
- Mamiko Noto
- Narrator
- Daisuke Ono
- Killer T Cell / Memory T Cell (voice)
- Rie Takahashi
- Lactic Acid Bacteria (Red)
- Yuri Yoshida
- Lactic Acid Bacteria (Black)
- Toa Yukinari
- NK Cell