Deathlord's weakness is to Stampeding Kodo or PW: Pain, and its true weakness lies on the decks lineup that we have.
For instance, if you have like 5 heavy drop legendaries, your chances of getting it from the decks is huge.
You can even pull out Ragnaros in turn 3/4.
It also weak to Corruption, this cards will have its place in Zoolock I think, to bypass an 8 HP Taunt is no easy task for Zoolock lol.