The Value of My Life is Priceless - S1.E11

Nagi, with Hayate, Maria, and Sakuya, go to visit the head of the Sanzenin family — Mikado Sanzenin. Hayate runs into him outside, but initially believes him to be a landscaper on Mikado's estate. 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 before leaving. Later, Hayate decides that he will protect Nagi from anyone that tries to hurt her, which greatly flusters Nagi.