That Janitor Is The Legendary Assassin King

Once the kingdom's most feared assassin, Kalen vanishes after his closest friend, Elion, sacrifices himself to save his life. To honor Elion's dying wish, Kalen hides as a lowly janitor and secretly protects the family he left behind. But when enemies threaten them, the man everyone mocked as a worthless nobody is forced to reveal the legendary assassin king he once was.