I was killing stuff on the Broken Shore when this dropped from one of my Emissary Cache's that I opened whilst I was doing stuff.
So at least I have a DH that is 100! However, it hasn't done any of the starter things - in fact, it's not gotten out of Vault of Wardens!
I attempted to do a little bit on my DH to get her out of Vault, and I made it to Orgrimmar before I got bored. But at least, I can use it if I get to Broken Isles and get to 101.
So... what's next?