Heartbreak and new love

A month after defeating Kokabiel, Issei comes back early from finishing a contract and overhears the girls talking bad about him and how much their boyfriends are better than him. He feels his heart break, but he's immediately comforted by Koneko who just came back from her mission. After that day, Koneko won't leave him alone, scares away any girls not approved by her from approaching him. She will do anything to make him happy. Even going as far as collecting a special harem for him with or without his permission.