Grim Walker

"Joen Sharn loosed the last of his many arrows into the Erderrni horde scaling the walls. He traced its arc, falling gracefully like a falcon, until it plunged deep into the eye of one of the Erderrni warriors. His grim smile turned into shock as the warrior, instead of falling to the ground, turned towards him and trained its remaining eye, visibly black as night, even from this distance, on Joen. The warrior started towards a siege ladder being erected near Joen, pushing aside any of the howling Erderrni in his path. Joen fled the battle, terrified of the revenant that stalked him, terrified so much that he took his own life with a knife three weeks after the loss of the city..." Narrative excerpt from Accounts of the Erderrni Invasion, by the Rhentairi Scholars. 
Not much is known about Grim Walkers, beyond the few reports of their appearance, using that of a pale, gaunt human with purple veins. These creatures are similar to Dark Walkers, with the exception that all have reported them as not being among the living. No one has been able to defeat them in battle, and the few that managed to flee reported that they would take mortal blows without flinching.