The Horn's Fate - Book 4 of the Ten Tears Chronicles

Goddess Nött ended Shannon's reign over the realm of Scardark, and thus, also thwarted the plans of the mad goddess of the dead, Hel. Nött, the wicked goddess of the night and a lover of desperate wagers, set Dana, the least likely of the Ten Tears to be trusted, on a hidden path for Midgard with the mighty Horn of Heimdall, Gjallarhorn, the key to the closed gates. 

Dana, having previously failed to guard her sister, and having foully betrayed her companions, must now find a way to unite what remains of the Ten Tears. On this almost hopeless mission to Midgard, the land of the men, Dana leads a volatile dragon, bitter Anja, and a dubious assassin Gutty to find the whereabouts of a long-lost First-Born. Should she succeed, she must also convince such a being to agree to restore Odin to his worlds.

At least Hel, and Shannon seem defeated, and Euryale and Stheno are both dead, victims of Shannon's ancient dagger Famine.

And yet, the Goddess Hel, despite her madness and greed for vengeance, is a meticulous, cruel planner who does not rely on one plan. Something odd is afoot in Midgard. Also, Dana's hidden burden is finally revealed. She must fight to keep her sanity and focus, as a powerful being inside her head is slowly corrupting her, aiding her when it suits it, and perhaps, by giving Dana even more power and greater skills, finally guiding her for a new destiny.