gravity falls descendents

We all know the regular gravity falls characters like dipper, mable, and gruncle Stan. but they are regular people they get old and pass away. Amanda pines is researching her family tree for a school project. she finds her family tree book in her attic while skimming through the pages she finds that her great grandpas, mason pines page is very interesting. What happens when she is visited by a familiar triangle demon while she is looking through her family tree book