Subaru Chiryuu

Shingos little sister who until recently was the only girl Shingo didnt fear mainly because she dressed like a boy. However one day she started dressing like a girl and recently has gone through a big growth spurt which makes her look much more mature to the point she is constantly mistaken for a teenager while she is in sixth grade. Subaru has a brother complex and is determined to be the only woman in Shingos life even wishing to have her brothers child and training to become her brothers woman believing under a misunderstanding that means going through bondage training where because of this she usually treats Shingos friends poorly tricking them to do chores around the house when they come over. Becomes extremely possessive and jealous when other girls hang around her brother. Their mother doesnt seem all too motivated to disapprove of Subarus feelings towards her brother and is even shown enjoying movies with incest even stating that the best woman for him would be his sister. Source: Wikipedia