Ijeiska, Jerga

He was the King of Gairadite and commander of the Demon King Subjugation Battalion two thousand years ago.

Jerga was Kanon's teacher and the hero that preceded him. Due to the death of his wife and child at the hands of the Demon King of Tyranny Anos Voldigoad, Jerga held a deep grudge against him and demonkind. Even after Anos sacrificed himself to end the war, Jerga did not change. He knew the Demon King would reincarnate in the future, so he set up the Hero Academy to pass on his hatred to future generations.

[Spoiler] Kanon strongly opposed the academy and its purpose, wanting peace with the demons instead. Afraid that he may complicate things, Jerga had his comrades pretend to be on Kanon's side before killing him. In doing so, he ensured his plan would be successful. Afterward, he altered the written history to ensure demons were viewed as cruel and evil, and even hid the fact that the Demon King willingly gave up his life to bring peace. [/Spoiler]