Ilmafirin's Comments

I did this on my demo lock and had very little problem with 7 of the 8 of the NPCs. You might want some friends to back you up if you're a squishier class. They don't appear as elites/rares, so people have little incentive to help fight them if you try kiting them into the open. They also reset if you die fighting them alone but stay active as long as they're in battle.

After I did the achievement, 3 showed up in my journal. I assume this is a bug, but who knows.