Anko is Torako's younger sister, Anko claims to be her sister's right-hand woman in her life. She is very affectionate towards Torako to the point it becomes obsessive, much to Torako's own horror. Anko is also a massive Yandere who will not hesitate to eradicate any girl that she believes is in a relationship with her beloved sister. Eventually, she enrolls in Hinominami High School and joins the Deer Club as a means for getting closer to her sister, appointing herself as her caretaker.