Hidden Mage Disguised as a Weakling — Episode 8

Top archmage Nathaniel hides his power and marries Commander Lucienne, backing her. After the war, she betrays him, bears traitor Jonathan's child, and covets his heirlooms. At the coronation, Nathaniel reveals his strength and exposes Jonathan's pact with Abyss beasts. Disillusioned, Lucienne kills Jonathan and seeks redemption at the border.