Weirduncle Stories

Imagine having an uncle, who has been around since the beginning of time. The family accepts him because, "Yeah, my grandpa knew him," so he is related. They never question why they can't see him in the daylight, but he comes to all the night parties. He has been around since forever, and they are cool with that. But I want to know more. When I find his house, full of magical trinkets and spell books, I am more than a little curious, but my curiosity gets me in trouble,