A Kakuja is achieved when a ghoul eats the organs or flesh of another ghoul with different kagune types. This causes them to absorb multiple different kinds of RC cells. Once this happens, a genetic mutation occurs and gives them the power of a Kakuja. This usually looks like your kagune is around your entire body instead of just being an organ that sticks outside of your back. A lot of times, it will resemble a monster, a huge example of this is Kuzen Yoshimura, AKA The Non-Killing Owl, and his daughter Eto Yoshimura, the one-eyed owl. They both take on monster-like appearances with their Kakuja. Though this only happens with a full Kakuja, most Kakuja that aren't complete will just cover part of the body, like Jason, who had an incomplete Kakuja, so it only covered his face and arm.