IMOUTO SAE IREBA II. GAIDEN: IMOUTO NI SAE NAREBA II!
Proper Japanese Title: 妹さえいればいい。外伝 妹にさえなればいい！
Serialized In (Magazine): Gangan Joker
— Description from Comic Vine community (comicvine.gamespot.com · https://comicvine.gamespot.com/imouto-sae-ireba-ii-gaiden-imouto-ni-sae-nareba-ii/4050-122113/).
