They are warriors with no names that save people, do damage control in battle areas and guard important facilities and key figures. Under Corps members, known more familiarly as "corpsmen", basically do the nitty gritty background work that keeps the Committee running smoothly.
The Under Corps consist mostly of supublics who failed the Sidekick-Hero course and thus failed to become sidekicks. Sidekicks that are dismissed by their master heroes are also expected to enrol into the Under Corps. Due to this, the Under Corps don't have the greatest reputation among supublics.
Corpsmen all wear the same dark olive green uniforms: males wear trousers, a two-button jacket over a form-fitting black undershirt, a black belt and a pair of black gloves while females wear a sleeveless dress and long black gloves that come up to the elbows. All corpsmen have black berets and glasses, although these don't have to be worn. On the chest of the uniform is a grey circle with a certain number of yellow (horizontal) lines across it.
- LINE sometimes translates their name as Undercore.
- It can be assumed that the number of yellow lines that a corpsman has, the higher their rank.