Shield of the Vanir - William R Humble - Bog

As the drums of war sound through Vanaheim, sixteen-year-old Arna severs her relationship with Maeve, resulting in heartache--and the loss of royal protection.
Soon after, Arna's brother Ragni is conscripted, and she loses her best friend, emotional support, and yet another layer of protection.
Left alone to care for her younger siblings, Arna flounders, and flees with the children to Yggdrasil to evade Queen Mab's wrath.
Provisions are scarce and new dangers lurk around every turn.
Arna must face her darkest fears and delve into her own burgeoning powers if the children are to have any chance of survival.