The Lost Monster Pines Twin\\A Gravity Falls Au

(This Story is based on my Gravity Falls AU, Beast Falls. It's basically like Monster falls but instead of the usual river incident, everyone in Gravity Falls are monsters. Dipper and Mabel were born but not raised in Gravity Falls. Grunkle Stan and Ford got custody of Dipper and Mabel the year after the twins turned 13 since their parents were deemed unfit to raise them. Bill is absent in this universe, since here, Bill managed to show his people the stars without destroying the dimension. Also monster features don't grow in until about age 6, some monsters can hide their features from the human eye, which was how The Triplets were born out of Town. There are more parts to the story that have been changed, I'll explain those in the second A/N chapter.)

//Marceline Stones, real name Marceline Pines, was taken at birth (Yes I know, this is pretty common in these kinda fanfics, leave me alone) by a nurse who wanted a daughter. The nurse told her parents she died in the nursery room and managed to sneak out of the hospital with Marceline. The way she hid her secret about Marceline from people was concerning, putting her in private school and using bribery and other things. Marceline's life was going great until she reached puberty.//

"I ran, I ran, and I ran, as fast as I could, I heard their gunshots and their yelling. I kept running even if I didn't hear them anymore, I was so focused on running I didn't even the 'WELCOME TO GRAVITY FALLS' sign, I was so scared, Why did this happen to ME of all people, why me? Just why? Why did I have to become THIS?"