I was really scared and even thought twice before reading this, especially knowing that it's his brother-in-law, despite everything, it's still cheating. But reading it completely really changed my mind. It is a masterpiece. The characters, plot, theme, and character development was beautifully written. Definitely one of my favorites now.
I'm proud of Yuki for trying everything he could to not tarnish his sister. And both of them never forgetting his sister. I love this!
Ani no Senaka