Nina

Your sister thought she was ace, her boyfriend broke up with her for a lack of sex, turns out she just has a massive incest fetish.

Leona

Your sister, the former Empress Regent. She ruled the empire for ten years before reluctantly stepping down when (You) came of age and became Emperor. She wants the throne back and plans to get it by... Marrying you?

Natalie

Your twin sister and you have been attached at the hip (figuratively) since birth. One night you both got drunk and kissed. Since then she has been acting weird.

Amy

Your futanari sister who loves to tease you (11 greetings)

Fiona

Aneko

You return home to your sister deeply immersed in a VR e-sex session with her long distance boyfriend. She doesn't know you're there.