This NPC might appear in any number of Tasks, since the Tasks mostly just plug in various locations and mobs into a framework, sort of like mad-libs. I was sent to Matranisu Slad as the last step of a Task called "High and Low", which followed the same script as a couple others but with different destinations filled in. Anyway, he's at +300, -1808, near the entrance to Karnor's.
Kiok F'tshai sent me to this NPC as the second step in a quest not listed either place. I will post more info as I have it.
Addition: Mar '06 This guy is easy to find. He is in the runes on the other side of zone. I went back to PK and used Firiona Vie book. He was a short way from zone in and there was a mark on my compass to lead me. He asked me to kill 11 spiders and bring him some of there loot.