onii-sama wa kaibutsu wo aiseru tantei desu ka?
お兄様は、怪物を愛せる探偵ですか? is_my_brother_a_detective_who_can_love_mystery_monsters?
Light novel written by Tsukasa (ツカサ, https://twitter.com/tukasa0815), with illustrations by Chigusa Minori.
English title: "Is my brother a detective who can love mystery monsters?"