Doom Lords are extremely rare occurrences which evolved rapidly from heavy exposure to a necromantic plague called the black doom plague. Doom zombies are what remain of creatures who survive the plague. They are completely black in color, within and without from the doom spores that utterly infuse them. These spores spread to others infecting anyone who comes in contact with these spores.

Powerful purification techniques and many other methods have proved fruitless in attempts made to cure the condition. The only cure for the black doom is to drink half a bottle or more of Spirit Water, a difficult to come by foul tasting water from Acheron's River of Souls.  It is only effective before the victim dies and rises as a doom zombie. Supplies of this water can be found in Seumir under control of the king.

The Doom King Morgir has developed techniques to control other doom zombies and contain the contagion in himself and others.  Finding one other like himself, Mendes, he passed on this knowledge to Mendes making him Prince of Doom.

Very specific anomolies in their immortal genetic makeup made Morgir and Mendes unique.  Both were shapeshifters, both euryalian, both part devil, one a powerful necromancer, the other a powerful wylde channeler, both highly intelligent. 

Of the two Morgir is more powerful as a Doom Lord owed to the dusky abyss dragon aspect of him. While Mendes wolf aspect allowed him less control but more resistances through the forces of nature he commanded.   As such he was not completely black like Morgir. Morgir's command over those inflicted with black doom was immaculate.  Mendes, while he could always summon them could not always control them right away.  They distrusted him, unlike Morgir.