Has a "slight" yandere vibe

No she's just like a beaten house wife. Her bitch of a sister treats her like utter shit and just sexually abuses her then tosses her to the side. Where are their parents in all this mess? This is one cruel story Aoshima thought up here, I have to admit it is interesting though. Hoping the abused sister takes a stand or just refuses to put up with the bs and leaves.