Ane Loop ☆ Kyuuketsuki na Imouto wa Docchi no Onee-chan o Erandara Ii no~!?

Riko, a vampire high schooler, enjoys a peaceful life under the care of her vampire sister Aru. But when a mysterious second sister suddenly appears at their home, Riko's tranquil world is thrown into chaos. Which sister should she choose to be with?