You can repeat the same stone over and over.
Once you have almost defeated one of the servants, he will be stunned for a fairly short period. If this happens close enough to the binding stone, you are then able to attack (by clicking on) the binding stone. You can be interrupted while destroying the binding stone.
You are able to tag the servant and drag it closer to the stone. It only has to be close to the stone when becomes stunned, for the binding stone to be click-able.
If you are interrupted, you may need to flee to reset the servant.
Servants of Grol
Found around the outside of Dreadmaul Hold. Also found in Dreadmaul Post (with the stone inside the cave).
Servants of Sevine
Found near the Altar of Storms.
Servants of Allistarj
Found along the east wall of the zone, between the Dark Portal to the south, and Nethergarde Keep to the north.
Servants of Razelikh
Found in the south and east, near the Dark Portal
https://www.youtube.com/watch?v=f0M8_cFB4v0
Also once, when a servant's hp dropped to %1 and he become immune to anything, the stone did not become breakable.. That's probably because I pulled him far off the stone so you better keep the servants and the stones close to each other.
Please do notice that even though the crystals light up (and you might be able to click a few of them), they do normally not become clickable before you get one of the objective mobs in low enough HP - if they're near the crystals, of course.
der konstante spawn ist richtig
aber
1) bring npc auf 1 % hp in der nähe von diesem stein
text: you notice the stone of bla...
1a) go wird anklickbar
2) npc stunnt sich selber
3) wenn npc in der nähe von diesem stein ist und stein angeklickt wurde > npc entfernt stunflag und man kann ihn angreifen und man erhält den killcredit wenn tot
Von 
Von 
Von