RC Cells. The RC stands for Red children. Both humans and Ghouls have RC cells; the difference between the two is the amount. A healthy Human has about 200-500 RC cells, while a healthy Ghoul can have an RC count higher than 1,000. ROS, which stands for RC Cell Over-Secretion, is a disease an human can catch when they have too many RC cells inside their body. This disease causes Kagune-like tumors inside their body. This is said to be extremely painful. and the resulting cause of these tumors is eventually Brain death. Ghouls can possess extremely high levels of RC without attracting this disease because their bodies have evolved to hold these RC cells safely.