The Disgraced Young Marshal

A humble young man returns to his family's luxurious mansion but is mistreated by security guards as a vagrant. When the family's head butler appears, the guards become overly eager, only to be shocked when the butler immediately kneels before the young man. It turns out he is the heir, having been exiled by his grandfather to the Black Blood Prison for five years to toughen him. His low-key return marks the start of his final trial as heir: helping the female lead's family reach the pinnacle!