The Raven's Children by Emily Barlow

Ambjorg, Asbjorn, and Audolf watch as their father, King Hrafn, wastes away before their eyes. Figures lurk in the shadows, waiting for the right moment to strike and steal the crown. And all the while the three siblings and their father share a secret: an affinity with animals they use to keep their homeland safe.

As tragedy strikes the royal family, reports of attacks by aberrant beasts start to trickle in. The siblings are split in many directions, thrust into new responsibilities that test their resolve and their bonds. It will take every skill and ally they have to best whomever--or whatever--is behind all the unrest. But will it be enough?

Or will they lose both their kingdom and the lives of the ones they love?