I Regard the Protagonist as a Good Brother

In order to make a contract with humans, the demon neighbor who has not been summoned by humans for a hundred years agreed to the system and traveled through a novel. Protect the weak and pitiful protagonist in the novel. Have a knife? He goes first. Was there a kidnapping? He went to save... Successfully allowed the protagonist to survive to the end. The task was completed, and the neighbor did not hesitate at all. He got the fruits of the transaction and turned around and returned to the devil world. As a result, a few years later, he saw a familiar figure in the demon world. Neighbor: "???" Neighbor: Is it too late to run away now? —— Xuan Ning's experiences since childhood taught him that everyone approaching him has a purpose. He walked among those people, wearing a gentle mask, but extremely disgusted. Until a strange demon appeared halfway through. At first Xuan Ning thought: Isn't a contract about using the other party to get something that is beneficial to oneself? Since the devil is willing to trade, he will definitely take advantage of it. Until later: Xuan Ning wants to own this strange demon. Too bad his demons got away. It doesn't matter, he will build a castle belonging to the devil and love the devil for the rest of his life. ————Received in advance———— "I am the pig teammate in the game" fast travel "Let BE Become HE" Quickly wear ————Final article———— "How to Stabilize the Protagonist" Part 1 "How to Save the Villain" Part 2 Mission: With love and courage, you can defeat darkness