Rook's beginnings were pretty unremarkable, until he and his siblings were old enough to start learning to fly. During one of their lessons, Rook and his sister were separated from the rest of the family when strong winds forced the weaker flyers to take refuge in the forest. Sadly, his sister fell to the ground, to weak to fly, and was killed by an opportunistic fox who just happened to be nearby. Since that day, Rook has harbored a deep resentment toward all mammals.