Gimai Seikatsu (義妹生活?, English: "Days with my Step Sister") is a manga series by Yumika Kanade distributed by ComicWalker digitally. It is based on the light novel series of the same name written by Mikawa Ghost and illustrated by Hiten.
Synopsis[]
This is a story that might lead to 'Love' one day...
High school student Yuuta Asamura ends up becoming siblings with a beauty at the same school and year as his, Saki Ayase, because of their parents remarriage. At first, they've decided to draw a line as they live their days, but eventually...!?
Thus begins the tale of a step-siblings romcom between your plain guy and beautiful gal!