Casca: Devil's Horseman (Casca: The Eternal Mercenary, #34)

The Mongols are on the move again and Russia is their target. Casca rejoins the Horde after an absence of nearly twenty years and finds the unity that Ghengis Kahn brought them is beginning to fracture. Rival factions vie to promote their favorite candidate to succeed the ailing Ogedei Kahn. Even as the Horde plunder their way through Russia, slaughtering as they go, Casca has to watch his back. It is when his woman is kidnapped by an unknown faction that Casca decides to take matter into his own hands and make the choice as to who should succeed to the throne. But first a war must be won.