The Loser Janitor is the Ultimate Legend2화

Thirty years ago, Grand Duke Cyril ended an alien invasion but lost his wife. He vanished into a janitor's life, raising his son, refusing wealth or titles. After saving a girl, he's set up with her mother, a tycoon. Mocked as unworthy, he stays silent until he reveals his identity, humbling his tormentors. The aliens return; corporations weigh saving the poor.