My Covenant with the Monster Lord

Yu Yin re-reincarnated back to the immortal world where he used to belong. An unfamiliar Demon Master, however, decided to mess with him. He even bit him and forcefully made a contract with him! Yu Yin was shocked while The Demon Master was impassive. Bei Xiao: “Now that we are already in a relationship. I must fulfill my responsibility! ” Yu Yin: “No, thanks.”