Yui's Sister (Diabolik Lovers x OC)

Yui's sister has been overshadowed by Yui all her life. Yui has always been perfect in the church's eyes. But Shizuoka has always been seen as a sinner. They even sent her to a military school when she was 8 years old, which is where she learned most of her combat skills.One day, her "father" informs her that she is to go to a distant relative's home in order to protect Yui.