Northern Wrath (The Hanged God Trilogy) by Thilde Kold Holdt

The first in an unputdownable trilogy combining Norse mythology and Viking history, for fans of The Northman and The Last Kingdom. The bond between men and the gods is weakening. A dead man walks between the worlds and foresees Odin’s doom. The only survivor of a slaughter unleashes a monster from fiery Muspelheim. Long hidden among mortals, a giantess sighs and takes up her magics once again. A chief’s son must overcome war and treason to become the leader his people need. And the final battle is coming...