Gym Gamma consists of a large, empty, enclosed space. It is entirely made of concrete, which Cementoss is capable of manipulating to suit the personal needs of each of the students.
It was created by Cementoss as a place where students could develop new techniques that could be applied on the Hero License Exam, under the supervision of Ectoplasm, Midnight and Cementoss himself. It was used by both Class 1-A and Class 1-B.
- Similar to the Unforeseen Simulation Joint, the initials TDL are a reference to the theme park Tokyo Disneyland.