Rift Mob:Buckley the Soul Stealer  

Buckley the Soul Stealer, Gloamwood

He stands on the hill by the Forest Altar across the Darkened Trace from Gnarlwood Post, blocking the way to the altar. All mobs in the area are level 19-20 making him a heck of a roadblock.

I'm unsure if the above is also correct or if this version of Buckley the Soul Stealer was simply left over from someone who did the encounter and failed, but Buckley the Traveling Merchant actually IS Buckley the Soul Stealer. Purchasing and selling to the merchant Buckley has a chance(?) of causing him to appear to you as you leave Gloamwood Pines, he offers special items and leads you off the path then transforms into Buckley the Soul Stealer and tries to kill you.

Here are some images depicting the encounter from back in head-start: [1] [2]