Kharn the Betrayer is a champion of Khorne.
Offical Canon
TTS Canon
Kharn was booked to appear for the Slaaneshmas special, but turned down the offer and grumbled on the phone. His slot was taken by Sly Marbo. He is acknowledged as part of the unofficial "quartet" of Chaos Champions, comprised of Ahriman, Typhus, and Lucius.