A Sister's All You Need (2017)

The story revolves around Itsuki Hashima who is a 20 year old novelist who is obsessed with little sisters. Despite his nature, he is admired by a small group of friends that includes a genius novelist Nayuta Kani who happens to be in love with him; Miyako Shirakawa, a girl from his college; Haruto Fuwa, a fellow male novelist and Kenjirou Toki, his editor.