Yk the one with the demon that's at the top of these pages (the non-hentai one is on here but I don't remember the name)
Ane Naru Mono http://www.mangago.zone/read-manga/the_demon_who_became_my_sister/?oyvO
Yk the one with the demon that's at the top of these pages (the non-hentai one is on here but I don't remember the name)