Finally, a satisfying theory (with heavy foreshadowing) for what George Martin is going with Rickon's story! Since Rickon is a child, George has based parts of Rickon's plot on children's stories - Where the Wild Things are and Three Billygoats Gruff - and these stories also foreshadow this endgame! Walder Frey is a bridge troll, Skagos is an island of monsters who ride goats.. come inside and  @GreyWasteTim  and I will explain!