Jerga

Jerga (ジェルガ, Jeruga) is the general of the Gairadite Demon Lord Suppression Army.

History
Jerga was in a strong grudge against the demons. After the wall is made and the Demon Lord died, it wasn't changed. The wall will disappear and the Demon Lord will reincarnate. He believed that the battle will not end until he completely destroys the Demon Lord. So he set up the Hero Academy to pass his resentment to his descendants.