Whispers of Spitfire: Spear of Cinders

From the back cover:

In the midst of a new ice age, brave shamans hunt gods born of black glass and steel. The blood of these gods is sacred, and the shamans of each tribe are marked with the sacred blood in ways that give them strange, supernatural abilities.

This is the sixth and final book in the story of the young shaman who walks between the tribes. When Singer-Of-Five-Tribes returns to Eikus, it is as an elder and a guide. A great hunt looms in the winter ahead, not only a hunt of the god of the Sun Elks, but a hunt also of Spitfire itself. Secrets from the last world will be laid bare, and the ways of things as the tribes have come to know them will be changed forever.