Hayate no Gotoku!

Synopsis

Nagi, with Hayate, Maria, and Sakuya, go to visit the head of the Sanzenin family — Mikado Sanzenin. When they arrived at Mikado's castle, the butlers and maids welcomed them, though they find Hayate a suspicious-looking person, which makes him feel depressed due to his poor luck. Hayate runs into Mikado outside but initially believes him to be a landscaper on Mikado's estate. Hayate explained to him about his debt from his parents. After Mikado reveals himself, he informs Hayate that his life is infinitely worthless while he is living to merely pay off the debt he owes Nagi. Mikado gives him a special pendant (King's Stone) before leaving. Then, Nagi ran to Hayate and tells him that they should return home. A man Gilbert Kent, a fake foreigner attacks Hayate. Before the fight, Mikado explained to Nagi that when he dies someday, Nagi will be the only one with the estate. Hayate can see what will happen if Nagi doesn't want to give up her estate in the future, and he defeats Gilbert with one kick. Later, Hayate decides that he will protect Nagi from anyone that tries to hurt her, which greatly flusters Nagi.

(Source: Wikipedia)