Engage Kiss

Shu lost his entire family in a special incident caused by demons called "D Hazards". He makes a contract with Kisara, an A-class demon, and she exterminates demons for him in order to solve past D Hazards and the mystery of the incident. The contract is to obtain the devil's power by kissing in exchange for his memories. A love triangle between a man, a devil, and his ex-girlfriend. With Kisara's great power, the truth is revealed little by little... Their uncertain bond teeters between love and contract. Where is their destiny headed..? (Aniplex)