Take A Closer Look: Dipper X HaftDemon!Reader

Old hero(s) Dipper and Mable Pines twins return to Gravity Falls for another 'fun' 'adventurous' Summer, with their great uncles - Ford and Stan, but just as the Summer begins to start, Dipper encounters a new girl called (Y/N) , though most people in town seem to show fear whenever she is around, just what about her is so scary as the Twins continue to discover more about their friend, Dipper and (Y/N) begin to grow closer...but time is running short for this demoness to reveal her true self- Either be like her Father and Destroy all in her path....or Be an Angel in Disguise