Unusual and Unexpected Families in Anime

People love drama. Why else would we devote several hours of our lives glued to our computer and/or smartphones watching some angsty heroine discover that she's actually an heiress who was switched with some other kid at birth? 

We anime fans, on the other hand, devote our time and satisfy our craving for plot twists and turns to series that have requisite "oh my, so she's actually the long lost sister who was kidnapped a long time ago?!" element that move us. Here are some of those shows.