Kaldor Draigo: Knight of Titan(2013)

Andy Smillie

A warrior without a war. A wanderer in eternity. A man shaped by destiny, but whose destiny is yet to take shape. Kaldor Draigo is all of this and more. Lost in the infernal otherrealm of the warp and doomed to battle the forces of Chaos for all time, the warrior who once led the Grey Knights Chapter to war is now a legion of one, with all the daemonic servants of the Ruinous Powers arrayed against him.

Read it because
It's a quick look at life for Kaldor Draigo within the warp, and at the lengths he must go to in order to remain alive and sane.