Yeah, ya cant split his companions...they move just as fast as he does and he makes a nice round loop runnin around the edges o' the goblin area..and he does hit hard..very hard..but ya do have time to heal yourself or your pet or have yer friends or mercs heal you..he doesnt stun often...unless yer too low level..oh and I couldnt snare this mob either
I tried three times to FD split him from the two stonemight elders with him. I was unsuccessful everytime. When Fd'd the elders stayed with him and never moved until he did - which made for a long wait.
Spawn location was: -1560, 801. He looks like the other goblins in the area, only slightly larger. Couldn't get a clean screenshot due to a multiple pull. He does see invis.
There is a small stone hut at that location where Stonemight Chieftain Rockbottom is located. He was one of the goblins located outsite the entrance of the hut, so presumably any of those could be the placeholder.
Loot: Smash Goblin Parts Amber A Stonemight Ear
When I pulled him the 2 goblins nearby came with him, even though they had been pacified with Nature's Placidity, so they appear to be linked.
Duoed with a 75 Pal/75 Dru. The mobs path weird in this area, probably due to the terrain being rough. They will "warp" short distances during the fight.