Rc (Red Children) cells (Rc細胞, Rc saibō) are certain cells that exist only in the story of Tokyo Ghoul. The origin of the name comes from how each individual cell looks like a curled up fetus. They exist in both humans and ghouls. They flow like blood but can become as solid as teeth, and could be called "liquid muscles". Typically, a ghoul stocks Rc cells by eating people. Within the body, the Rc cells are concentrated and stored in a kakuhou. The kagune is formed by Rc cells that have been released from a kakuhou and have pierced through the skin.
Rc Factor and Level
The Rc factor is a measure for the amount of Rc cells in the body of a living being. Ghouls have an "Rc factor" ten times higher than humans. The average healthy human has an Rc factor of about 200 to 500, while a ghoul has an Rc factor of about 1000 to 8000. If, for whatever reason, a normal human receives an excessive amount of Rc cells, such as through experiments, they will start to develop ghoul-like characteristics and eventually not be able to consume human food.
Rc Cell Vessels
Rc cells flow through specialized Rc cell vessels. They spread from the kakuhou and permit the body to produce a kagune to the outside. The bodily capabilities can increase as much as the number of vessel increases. Vessels grow and spread throughout the body, stimulated through repeated injury and regeneration. Through this process, half-ghouls and quinx become stronger to the degree they're hurt. It is unclear if normal ghouls can become stronger this way, too.
- Rc cells are also vulnerable to genetic problems, a notable example being the Tsukiyama family's apparent inability to develop even a half-kakuja.
- Some humans suffer from a genetic disease called ROS, where the victim secretes an abnormal amount of Rc cells.
- Highly concentrated Rc cells can ignite and produce flames that are 4000°C (celsius) or form lightning-like projectiles.
- The highest Rc level stated in the series is 10181, Koutarou Amon's level after being experimented on by Dr. Akihiro Kanou.