Mal'koss, briefly disguised as a warpriest, was an avernic demon who sided with the Mahjarrat general Zamorak during his betrayal and ultimate assassination of the deity Zaros during the Second Age. During Children of Mah, he is encountered in Kharshai's memories of the betrayal, disguised as a female human warpriest. After his disguise is revealed, he is found to be a traitor, and Azzanadra orders Kharshai to either spare him or execute him. Regardless of player's actions during the memory, Kharshai executes him.
- In his human form, Mal'koss appears to be wearing Zarosian war robes.
- He uses the same in-game model as Kal'Ger the Warmonger, his subdued animation is the same as Yk'Lagor the Thunderous' before he breaks free.