Is that random mistaken nonsense, or is there actually some link between Malacath and Orkey? Since Orkey is the Nordic version of Arkay... how in the world would that work out?
Additionaly, considering the origin of Malacath, is he technically a Daedric Prince?
And one more thing, while I'm intruding upon your time - What's the source of that myth about Orkey cursing the Nords to have briefer life spans? I've never seen it in-game.