Winterwall — Rick Nichols

Cain, the Eastland Blademaster, finds himself stranded along Grayrock's northern Wall, a barrier that protects Grayrock from the barbaric tribes in the north just beyond the mountains. But trouble is brewing. The tribes are leaving their lands to travel over the mountains and raid along the Wall. In addition, Nyogi, the Eastland assassin who Cain pursues, has hired skilled Talon assassins to find the Blademaster and kill him.
Riding alongside battled-hardened veterans and scared new recruits, Cain must help defend the Wall in the face of a fierce winter storm. When Jessup, Lord of Grayrock, arrives for a inspection before winter, the stakes get higher with the discovery that there is something more dreaded in the snow than a barbaric tribe, something from Ancient times and it has returned, hungry for the taste of men.