My Sister Picked Up The Male Lead

Briefly about My Sister Picked Up The Male Lead manga: 

When I, Amy Lamias, turned six, I told my sister that I dreamed of having a friend… To my surprise, ten years later she brought a child into the house.

Read My Sister Picked Up The Male Lead Manga.

But it wasn’t her child, it was a damned sociopath who was the main character in the book. It happened exactly like a scene from a love story I had once read.
Yes, I knew it was the main character, and I knew we were in for a grim future. There was a curse on him that made him take the form of a child during the day, only returning to his true form at night. I was afraid of what would happen one day, so I wanted to run away. But he appeared right in front of me…I had no choice but to pretend to be nice to him.One day I gave his baby version a name, Knox. After that, he started following me everywhere like a puppy. That same night his adult version caught me off guard when I went to check on him…