Transmigrated into a Book as the Scumbag Villain Brother: I Spoil My Crazy Heroine Sister

Lin Tianyi transmigrated into a book, becoming a villain. The heroine was his younger sister. He was the Lin family's adopted son, and they doted on him, while showing little love for their own biological daughter. After learning the plot, Lin Tianyi knew that once his heroine sister rose to power, she would take revenge. So he started spoiling her. As long as I spoil my little sister, she won't kill me! That's right! Exactly! If I spoil my little sister, she won't kill me!