A Sister's All You Need (妹さえいればいい。 Imōto Sae Ireba Ii.) is a Japanese light novel series written by Yomi Hirasaka and illustrated by Kantoku. Shogakukan has published seven novels since March 2015 under their Gagaga Bunko imprint. Two manga adaptations have been published by Shogakukan and Square Enix. An anime television series adaptation by Silver Link premiered on October 8, 2017.