Freya the Huntress: Europa (Volume 2)

Freya the Huntress is Book #2 in the EUROPA dark fantasy trilogy:

When Freya's sister is bitten by a horrific beast, she has only a few hours to find a cure before her sister turns into a ravenous fox demon. 
With her husband Erik and the young witch Wren, Freya explores cities of the dead and finds survivors on the edge of madness. She finally seeks answers in the ancient city of Rekavik, where she meets the deadly witch queen Skadi and the vicious warrior Leif Blackmane.

But the only person who can cure the demon plague is the person who created it in the first place, a stranger who carried a sword full of captured souls, a man who was murdered five years ago... 
Discover a fantasy world where strange machines sail the seas and the skies, enormous prehistoric beasts roam the earth, and the restless dead whisper to the living.