If you mean "Deathkings of the Dark Citadel", technically it works fine, it's just game balance that might be a prob as it was never tested.
Simply copy hexdd.wad from your "Hexen: Deathkings" directory to the Korax Mod or Korax Mod II dir, then open autoexec.cfg in a text editor, and add after the last line following: load hexdd.wad. Make sure you make an extra carriage return after this entry, or the engine won't load it. If you did it right, the game should start up with the HexenDK start screen instead of the custom KMOD one.
Another possibility is that instead of adding it to autoexec.cfg you start up the game, pull down the console and type in load hexdd.wad, then start a new game from the menu. The preferred method depends on how many sessions you want to play the mission pack.
We didn't play through any of the mods on the HexenDK levels. Since enemies are more and tougher, you might have more of a problem at start, OTOH you will advance levels faster. It might be playable, especially on lower skills. Also, since there is no way you get to a shop when playing the Deathkings maps, Korax Mod (the first one) might offer a more balanced gameplay for the mission pack.
Anyway, if you get into those hubs and can get through, be sure to share your experiences with us so we know how it works. [img]images/smiles/icon_smile.gif[/img]