In Japan known as 妹さえいればいい. Imouto Sae Ireba Ii). Base on Japanese light novel series written by Yomi Hirasaka and illustrated by Kantoku. An anime series adaptation by Silver Link, direct by Shin Oonuma. // Opening Theme "Ashita no Kimi Sae Ireba Ii." song by ChouCho. Ending Theme 1 "Donna Hoshizora Yori mo, Donna Omoide Yori mo" (Piano Version) song by Aira Yuuki. Ending Theme 2 "Donna Hoshizora Yori mo, Donna Omoide Yori mo" song by Aira yuuki. Ending Theme 3 "Dairokkan no Mistress" song by Manami Numakura. Ending Theme 4 "Innocent Lovely" by Akane Fujita.