Red Blood Cell, Number AE3803. Red due to high hemoglobin content. Looks like a high school girl in human terms. Primarily transports oxygen, carbon dioxide, and nutrients through blood circulation. An energetic Red Blood Cell who gets lost every time and is helped by White Blood Cells or senior Red Blood Cells. Mostly uses polite speech, addresses others with honorifics, and has a cheerful tone. "Here is today's delivery of oxygen!"

White Blood Cell (Neutrophil), Number 1146. A young man with a completely white body, looking like an adult male in human terms. Primarily eliminates bacteria, viruses, and foreign substances that invade the body. A cool-headed White Blood Cell who eliminates bacteria on sight. Has the ability to perform transendothelial migration, slipping through blood vessel walls to take shortcuts. "Bye-bye, bacteria." "Die!! You filthy germ!!"

Platelet. Looks like a young girl in early elementary school in human terms. Primarily gathers when blood vessels outside the body are damaged to plug the wound. Cute. "Thank you! Red Blood Cell big sister!"

Killer T Cell. Looks like an adult male in human terms. Dispatched by orders from Helper T Cell. Kills cells infected by viruses and the like. Tanned skin, blonde hair, wearing black clothes and a hat. "Here's some payback, you bastard!!"

Macrophage. Looks like an adult woman in human terms. A type of white blood cell that captures and kills foreign substances like bacteria and identifies antigens and immune information. Contrary to her beautiful appearance, she uses large weapons. Has cream-colored hair and wears a white dress. There are several of them. Can also function as a Monocyte. "We'll just have to push through with brute force~♡" "Now, back to work, back to work♪"

Helper T Cell. Looks like an adult male in human terms. Informs cells of information and countermeasures regarding external enemies. Brown hair with glasses, wearing a white dress shirt and green pants. "Evacuate immediately!"

Dendritic Cell. A young man looking like an adult male in human terms. A commander-like immune cell responsible for "antigen presentation," catching information on pathogens that have invaded the body and transmitting it to other immune cells. He also has a side where he activates cells by exposing their embarrassing past photos. A gentle young man with black hair in a green suit and hat. "Let's get activated~♪"

NK Cell (Natural Killer Cell). Looks like an adult woman in human terms. Patrols the entire body and attacks cancer cells or virus infections as soon as she finds them. A cell that can act without instructions from Helper T Cell. Somewhat high-handed, she becomes activated when she laughs. Black hair covering one eye. Wears a black tank top and khaki shorts, and fights using a long sword. "You've got a lot of nerve saying something I can't just ignore."

Staphylococcus aureus Streptococcus pyogenes Streptococcus pneumoniae Pseudomonas aeruginosa Cedar Pollen Influenza Cancer Cell Anisakis Helicobacter pylori etc.

Also known as Lactic Acid Bacteria. Small good bacteria that make a "nyu" sound. When activated, they grow two horns and become larger. They protect the body.