Edmaris Falmuth/Chronology

Demon Lord Awakening Arc
Edmaris is first introduced preparing an invasion on the Jura Tempest Federation due to it reducing the profits from tariffs Falmuth received from being the "gateway" to the Armed Nation of Dwargon, as well as anticipating the prospects of gaining the Federation's resources for his own country. Because of reports of Rimuru's humble attitude, lacking proper intel about his true strength, and being unaware of Rimuru's identity of an Otherworlder, he misjudged the situation and started an invasion on Tempest's Capital, the City of Rimuru.

After getting his army of 20,000 soldiers wiped out in his confrontation with Tempest, he attempted to flee with Archbishop Reyhiem and Courtmage Razen only to be stopped by an angered Rimuru. He tried to plea for his life by telling Rimuru that he was just trying to create diplomatic relationships. This of course was a lie so Rimuru caught him with the other two and sent him to be interrogated by Shion.

Saint-Monster Confrontation Arc
Edmaris was put under the effects of Diablo's Unique Skill Tempter alongside the other two survivors. Not having any intent on resistance left, he followed Diablo's script and abdicated his throne to his little brother Duke Edward.

Edward then launched a civil war and tried to stage an offensive against the retired Edmaris with the Holy Western Church's backing as part of a scheme for Edward to invalidate the obligation to pay reparations to Tempest. But when three of the Clerics of the Seven Luminaries appeared and showed intention to kill everyone present, Edward gave into all of Diablo's demands and shortly after Diablo killed the three Lumiaries, Edward handed the throne to Youm, marking the end of the civil war.

After Youm became the king, changed the name of the kingdom into the Kingdom of Farmenas and received the new name of Youm Farmenas, Edmaris served Youm as his adviser.