As one of the many easter eggs, hearthstone crosses over into Draenor with the hearthstone garrison mission. While the prize is pretty good, it does override traits.

The opponents are all popular hearthstone decks, zoo, miracle (less so now) and control.

The usual method is to throw onto the lowest level 90 and up follower with no useful traits.

The associated meta text dealing with hearthstone is pretty funny

hearthstone master wow hearthstone mission