since the launch of don mpg has been a bit broken. at least was last time i went there a month ago. a lot of spawns are now out of location. and a lot of rooms now stand empty. i reported this but was told nothing was wrong.
Either this guy can spawn in more than one place, or Arocus is dead wrong. I saw him spawn in a dead end a bith south of the Taskfiend today. He dropped a lesser rune and the Stone.
He spawns in the circular room just south of the Girplan Scavenger. Not very convenient as a camp, going thru the north passage in 6way (or whatever your server calls it) and west some.