The Ranger of Marzanna

When their father is murdered by imperial soldiers, two siblings set out on opposite paths--one will destroy the Empire forever and the other will save it--in this thrilling new epic fantasy.
Sonya is training to be a Ranger of Marzanna, an ancient sect of warriors who have protected the land for generations. But the old ways are dying, and the rangers have all been forced into hiding or killed off by the invading Empire.
When her father is murdered by imperial soldiers, she decides to finally take action. Using her skills as a ranger she will travel across the bitter cold tundra and gain the allegiance of the only other force strong enough to take down the invaders.
But nothing about her quest will be easy. Because not everyone is on her side. Her brother, Sebastian, is the most powerful sorcerer the world has ever seen. And he's fighting for the empire.