The Lightforge Mace was actually supposed to be given as a quest reward by Tremain the Priest after the quest Archbishop Lazarus which was originally given by him has been completed. This Unique Mace was never really implemented into the game with exception for that it is only obtainable in Single Player and even then only if a Crackrust is dropped first, however it will most likely morph into another item after one has created a new game and be gone.