While you were battling the evil forces of D'Sparil, the other Serpent Riders were busy sowing the seeds of destruction in other dimensions. One such dimension is the decaying world where Hexen takes place. A world littered with the mangled corpses of nonbelievers and inhabited by the undead followers that executed them. Only three humans &endash; a warrior, a mage and a cleric &endash; have escaped the leaders' vicious spell. Now these brave souls have sworn to crush the evil regime that threatens to destroy the world forever. Separated upon entering the mystical portal, the three are forced to attempt on their own what they had hoped to do together: find Korax's stronghold, destroy him and restore order in the physical world.
One of the best semi-"total conversions" for Hexen that touches upon almost every aspect of the game. Introduces actual RPG elements with leveling, attributes, special abilities, skills, and class focuses. Adds new classes, weapons, enemies, items, accessories/artifacts, and an alchemy system.
The author recommends Zandronum, but it works with (G)(Z)(L)Doom too. Actually, it's the patched version of the newest WoC release compatible with the newest GZDoom release(s).
It's strongly recommended to add it to the load order for (G)(Z)(L)Doom/Zandronum source port via some launcher (like ZDL or QZDL or DoomLauncher).
Found on ZDoom forum. Visit it for more details. The mod has its own (not complete) Wiki page as well.