Bluetracker
Tracks Blizzard employees across various accounts.
Malorne - Confirmed to work with BOTH Kel'Thuzad and Baron Rivendare
I had been hearing both that Malorne did and did NOT work with Baron Rivendare/Kel'Thuzad, so I decided to test it for myself. I can confirm that he works with both card affects. As you can see, when he killed by a big game hunter, two Malorne appeared in my deck from the Baron Rivendare affect of his deathrattle activating twice, and he also stayed on the field because of Kel'Thuzad! Malorneception!
Zeriyah
Oh deer - that's interesting. We tested it previously and that interaction was only producing only one Malorne, but we'll take a look at it and see what makes the most sense. Thanks for bringing this up!