Maou desu. Onna Yuusha no Hahaoya to Saikon Shita no de, Onna Yuusha ga Giri no Musume ni Narimashita.

Meet Galt Luzen, the Demon Lord. Well, the Demon Lord of his own continent, anyway. After his wife passed away, he gradually withdrew from his social life and started to do more of whatever Demon Lords do.