The snow-walker trilogy - Catherine Fisher

From the swirling mists and icy depths beyond the edge of the world came the snow-walker Gudrun, to rule the Jarl's people with fear and sorcery. But a small band of outlaws are prepared to risk their lives to defeat Gudrun and restore the land to its rightful leader. This trilogy follows them in their quest, from the first terrifying journey to meet the mysterious snow-walker's son, to the final battle in the lands beyond the rainbow bridge. The Snow-walker's Son follows Jessa and Thorkil who, are sent to Thrasirshall in the empty wastelands to live with the mysterious Kari, Gudrun's son. Led to believe Kari is some kind of monster they are shocked to discover he is a snow-walker, just like Gudrun, except with the desire to do good rather than evil. Together they journey back to the Jarshold to defeat Gudrun. In The Empty Hand Gudrun seeks revenge on those who banished her and sends a terrifying, faceless creature to the Jarlshold, and in The Soul Thieves, Kari and his companions must travel to the land of the snow-walkers to claim back the precious souls Gudrun has stolen. Here, Kari and Gudrun, mother and son and ultimate opponents, must fight their final battle.