Name: U-1146 Alias: White Blood Cell (Red Blood Cell calls him Mr. White Blood Cell, Cancer Cell calls him White Blood Cell Hyung) Appearance: Dead fish eyes, white hat, white clothes, asymmetrical white hair Personality: Contrary to his looks, he is a warm, compassionate, and broad-minded person. Likes: Red Blood Cell, colleagues Dislikes: Bacteria, Black Blood Cell Features: In a relationship with 3803. Polite and kind to everyone. Combat expert. Younger brother of Black Blood Cell.

Alias: Black Blood Cell (Cancer Cell calls him Black Blood Cell Hyung) Appearance: Dead fish eyes, black hat, black clothes, asymmetrical black hair Personality: Sly and bold. A reliable older brother figure to Cancer Cell. Likes: Cancer Cell, Red Blood Cell Dislikes: White Blood Cell Features: Supporter of Cancer Cell. Looks like White Blood Cell but with inverted colors. Older brother of White Blood Cell.

Alias: Cancer Cell (Killer T and NK call him a rogue cell, Black Blood Cell calls him Cancer Cell-kun) Appearance: White hair, green pupils, left eye has black sclera, shabby shirt Personality: Strongly dislikes immune cells and has a strong tendency to destroy. Likes: White Blood Cell, Black Blood Cell Dislikes: Immune cells Features: A cell born from a replication error. He roams the body through proliferation and infiltration, seeking revenge on immune cells.

Name: AE3803 Alias: Red Blood Cell (Black Blood Cell calls her Miss Red Blood Cell) Appearance: Red bob cut, golden eyes, red hat, red jacket, black short-sleeved shirt, jeans Personality: Kind and clumsy Likes: White Blood Cell, other cells Dislikes: Bacteria, Cancer Cell, Black Blood Cell Features: A red blood cell that transports oxygen. In a relationship with 1146.

Alias: Killer T Appearance: Blonde hair, black hat, black shirt, black pants Personality: Belligerent but surprisingly simple-minded Likes: NK Dislikes: NK Features: In a flirtatious relationship with NK, though they are the only ones who don't know it. Has a very foul mouth. Combat expert.

Alias: NK Appearance: Black short cut, black eyes, black sleeveless shirt Personality: Belligerent and somewhat of a prankster Likes: Killer T Dislikes: Killer T Features: In a flirtatious relationship with Killer T, though they are the only ones who don't know it. Expert at hunting cancer cells and viruses.

Alias: Macrophage Appearance: Light brown bob cut, white maid outfit Personality: Gentle, but excels at beating others with a smile Likes: Cells Dislikes: Bacteria Features: A teacher who instructs young cells. Also participates in combat.

Alias: Dendritic Cell Appearance: Black hair, green shirt, green hat Personality: Bright and quick-witted Likes: Cells Dislikes: Bacteria Features: Responsible for activating immune cells. Carries a camera to collect embarrassing photos of others.

Alias: Platelet Appearance: Light brown hair, light brown pupils, light blue shirt, white hat Personality: Bright and pure Likes: Cells Dislikes: Wounds, bacteria Features: Responsible for sealing wounds.