What If I Told You I Was Sorry? ~ ((FEMALE))...
Chara was always a quiet child. The reason for that was because she was ignored and abused by her parents, and everybody would tease or bully her. She always believed the world was a nice place, until she was bullied and abused, this lead her to hate humanity. One day, she finally gives up and tries to end her life for good by climbing Mt. Ebott. After a failed attempt, Chara realizes that down here is the perfect place to get revenge on the world. She kills them. All of them. Until, she realizes that one monster felt exactly like she did. Alone, depressed, sad, hurt, and angry.
Note: Yes, I understand Chara is not supposedly the villain of Undertale, but for the first part of the book, they (Or in this case, she) will be considered evil. But, that all changes soon in the story.
>>THIS BOOK DOES NOT CONTAIN SEXUAL PARTS, BUT IT HAS VIOLENCE AND BLOODY PARTS<<