A Sister's All You Need
妹さえいればいい。, It'd be Good if Only Little Sister Was Here, Imouto sae Ireba Ii.
This is the story about the daily life of a young siscon novelist, Itsuki Hashima with his perfect little sister Chihiro, the genius illustrator Nayuta Kani, his best friend Miyako Shirakawa and some insane partners from his publishers.