there's something about 2 intense clearly mentally unstable characters and the dynamic of their insatiable love that makes my brain short circuit. I really enjoyed that there was a route where the main character could see the horribly flawed mind of Chao without responding in utter disgust, but instead responding with intrigue, and the love/obsession simply intensifies. I don't know why but it just makes something in my brain click. I obviously don't think the actions of the character is okay yada yada, but I like the intensity and passion. :3
Tldr: I like that there's a route with intensity of the flawed love interest without the main character being disgusted.