Tbh, this is one of the better one i've read. The "brother and sister" tag shouldn't really be there, since they aren't brother and sister by blood nor law. The little uke summons the demon ( AKA big sister ) and basically wants an older sister. But they kiss and are a little touchy touchy... But I gotta say, that demon girl can be my sister anytime. Do my hair and help me go through life as a woman, also wouldn't mind touching them boobs.
The Demon Who Became My Sister