Merlin's Apprentice: Warrior Rising

Young Pip must embrace his power to become a battle mage so he can defend the Magic Realm against the fierce Northmen invading from the sea and from the dark forces attacking his kingdom.

While recovering from Mordred's reign of terror and the departure of King Arthur, Pip foresees a new enemy breaching the shores of Britain: a fleet of Northmen led by the ruthless Halfdan Ragnarsson. Pip and Merlin fear Ragnarsson will fill Mordred's void and bring demonic darkness and chaos to their realm. It falls to Pip, together with old friends and new magicked allies, to stop Ragnarsson, protect the magical barrier that separates the Magic Realm from the Realm of Faerie, and unite the mages of light to protect all who were scattered by the breaking of the worlds.