The Prince of the Icemark (The Icemark Chronicles: Prequel)

The shieldwall shattered. Werewolves poured through the breach, teeth and claws slashing and rending. Vampires dropped from the sky, landing inside the smashed ring of shields.
The cavalry was ripped apart by the werewolf phalanx, horse and rider brought down under a tangle of teeth and claws. The surviving horses ran in terror, trampling human and foe alike. All around was chaos and death. Soldiers scrambled away as best they could, throwing aside shield and armour and anything else that slowed them down.
Nearby the boy could see his brother, King Edward, standing with his war band of bodyguards. They were surrounded by werewolves and fighting like cornered animals.