Solo'd with a 37 druid and got it from a Syndicate Conjuror on 7th kill, keep to the central road if your by yourself and pick off the Prowlers that patrol down that way, you can drag them off to the first level from the second and then off towords the defenders, but be sure not to get too close being that they or the 38+ ogre that patrols right there can get you. As well watch out for the 38+ Knight that partols on horseback with 3 36+ guards, he comes in and out the defenders area and out the front gate. Once you pull out a couple of prowlers out and dispose of them, you can pick at the Conjuror on the second level to the left (thats where i got mine, fyi the minions a wuss 36) but if you try this STAY TO THE WALL FARTHEST FROM THE KEEP, there are at least two more Prowlers against the wall for the keep at any time. The key as they said before is taking em one at a time, if you aggro a group bolt out the front gate and come back later.