Hello. I'm a DK. Perhaps you've heard of us? I've killed my plenty of priests and shammy 1 on 1, and cut down a forest of trees. It's not easy, (especially druids) but it's very doable.There are a few classes that can wear down a healer, but none are able to outright solo one on their own.
strangulate/ghoul stun off the bat, mind freeze after it wears and they try to heal, then finish them off. My diseases counteract a heavy portion of a druid's dots. Add war stomp into the stun list, but that's just a perk of being a sexy bitch tauren.
XI Wiki



