Jerga

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

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