Magical Girl Elena / Mahou Shoujo Elena

It has been 10 years since the car accident in which the parents of the main heroines, sisters Elena and Emily, died. They were left alone and must watch over and care for each other. One night, a loud scream rang out in the sisters' house, Elena immediately went to her sister's room and saw a terrible sight... Emily is being raped by a tentacled monster, Elena panics and cannot understand how to save her sister, and at that moment HE arrives - a savior in the form of a "flatcake" named OVI...