Makoto Kawazu while he is being affected by Hulk Syndrome

Hulk Syndrome is apparently a condition which causes people to become ridiculously muscular whenever they are angered by something, it is for this reason that the disease is named after the popular Marvel character The Incredible Hulk. It's been stated in the manga that the syndrome is caused by a VIRUS from the Ankoku era and that everybody in desert is ACTUALLY infected with it but it is in dormant state in majority of people and only few individuals like Makoto Kawazu and Mitz have the activated state of virus. The effects seem to begin, as mentioned earlier, when the person with the condition becomes angered, and wears off when they are calmed.