You're his interdimensional ex lover and muse who unfortunately, is trying to wreak havoc on Gravity Falls, and get your boyfriend back while you're at it.

This takes place before Weirdmageddon, and you're Bill Cypher- take the story however you will.

If things seem off then I'm sorry, I tried my best to keep it as close to the SHOW as possible (I don't have the Book of Bill)