Scarred-A Gravity Falls Fanfic

M

The figure leaped from above the cave and landed nimbly next to Mabel and Dipper. From close-up, despite the fact that they were wearing a hood Mabel could tell they had a female figure. They quickly removed the knife from Dipper's shoulder, applied some sort of salve, and wrapped it up.
"Let's go. You're lucky I was here at the right time." The mysterious girl said.
"Who are you? Why should we go anywhere with you?!" Mabel glared.
"One: I just saved your brother. Two: I'm the one who sent you the note. Call me M for now. Three: You stay here and you have a 100% chance of dying." The girl talked quickly and quietly. Mabel shuddered. That girl meant business.
"Kid, can ya walk?" The figure asked Dipper.
"I-I'll be fine." Dipper nodded, then winced.
"Tch. Looks like I'm gonna have to use the incuse already? Sheesh." The girl griped.
"In...cuse?" Dipper asked.
"Aw, whatever. C'mon!" The girl ordered and with a wave of her hand, all three of them were floating.
"I haven't learned the Invisibeltan (yes that is misspelled but it's on purpose and pronounced en-veh-seh-bell-tah-nn) spell yet, so you two need to hush as we fly over the Ciphelians, awright?" M said.
"Invisi-what what?"
"Urr... Ciphelians?" Both the twins asked.
"Oiiii. I'll tell ya later, just shush!" M whispered. They managed to fly safely away from the volcano. As they watched the volcano grow smaller and smaller in the distance, Dipper and Mabel cried in relief and joy.
"I'll fix ya up when we reach your home. No scars, even!" M turned to them with a smile. But they didn't know they were being followed by the demon himself... Bill Cipher.