I was killing the Earth elemental invaders with my SK and Pally, and i killed alot of hem, then i saw something in my chat screen saying: Earthmaster Grundag shouts, Why you destroy the powers of earth? You will be smashed! So i was like, omg now hes gonna kill me! But he didnt came after me but i think i spawned him :D
All previous posts seem to be right on. Just me and a merc cleric (lvl 67 Chanty with 865 AAs); zoned in invised thinking to scout the area and went to +874,-131. He wasn't there at first but attacked from behind as I was making notes on my map. He was my first kill after zone-in so I assume random spawn. Yes, he sees invis and summons but not too hard with a fully buffed pet and Tier I healer.