Yandere!Bill Cipher x Male/Reader x Yandere! Dipper Pines

The New Boy

Two months ago, a big mansion was build. It was owned by a very rich family but only two boys were seen.

The youngest was loved by everyone while the oldest was feared.
(M/N) (L/N) was the youngest and was usually mistaken for a girl because of his feminine body. You had shining (e/c) and (h/c) with a line (2nd/h/c) at the front of your hair.You wore a (f/c) hoodie with black short shorts. You also wore long white sock that reached your knees and black shoes. 
You had a strict older brother, named Xander (L/N).

The next day, the brothers decided to walk around Gravity Falls. The first place you both went was the mall. You pleaded your brother to play the games at the arcade and because you were giving him the cute look he sigh in defeat and allowed you to play.

After that, you both went to other interesting places. 
Lastly, you both went to... "Mystery Hack??" you said. "It's Mystery Shack.The letter 'S' fell." Xander said. "Oh." you said. 
You both entered the shop and you were looking around, examining the shop. Xander looked at a teenage girl that had brown hair. "I'll go there,okay?" Xander said walking to toward the teenage girl. You walk toward a man with an eye patch man that was wearing a black tux. "Hello, sir!" you said. "Hey,kid. Are you new here? Never saw you around. If you are, let me give you a tour around and that will be $10! " he said. "Sure but maybe some other time! Thank you for the offer!" you said then walk toward two twins that had brown hair.

"Hello~ Nice to meet you. I'm (M/N) (L/N)." you said,cutely. Dipper blush and Mabel noticed. She teased Dipper by nugding Dipper's shoulder. "Hi! I'm Mabel Pines and this is my brother Dipper Pines." Mabel said, cheerfully. You smiled at her cheerfulness and Dipper smiled still blushing. "You must be new here! Wanna be our friend??" Mabel screamed and you flinch a little. "Sure!" you said and Mabel pulled you to their room.
Once you reached their room , Mabel spinned you around before she pulled you on her bed, making you both jump. "Hey! What bout' , I go grab us some snacks. By 'I' , I  mean me and Mabel." Dipper said and both Mabel and Dipper went to get snacks. 
You looked around their room and found an interesting book. You took it and saw a hand that had six fingers with the no. 3 in the middle. You look through the book and found a page that had a story about Bill Cipher. You read the a text that was beside the picture out loud and a yellow flash appears. You saw a man dressed in a yellow tux with a black hat on his head holding a stick.

He smirked and introduced himself. "Hello, there. My name is Bill Cipher. " he said putting a finger under your chin. You were scared so you started crying. Mabel and Dipper heard you cries and ran up. They saw Bill and pulled you behind them away from the demon. Bill growled and glared at the twins. "You do know I'm a demon so I'll claim your little friend as mine~ Just you wait!" Bill said and dissapeard. 

Your cries turned into sniffles. "Don't worry (M/). We will protect you, right Dipper?." Mabel said , smirking at Dipper. "Y-yeah." he said, blushing. You giggled and played some games.