Image via WikipediaVecna was a powerful wizard who became a
lich (someone who uses evil magical power to allow his or her continued existence after death in an
undead state). His material body was eventually destroyed, and his left hand and left eye were the only parts of his body to survive. Before his bodily demise, Vecna manipulated the energies of the universe and began his transcendance into godhood, ruling the dark realms of man and monster similar to Hel, Khali, Hecate, Loki and many others. Even after he achieved godhood he is still described as missing both his left eye and left hand.
When the false god
Diablo and his unholy brothers Baal and Mephisto were once again unleashed upon the world in the small realm known as the lands of Sanctuary. Though the realm was small, the unholy trinity threatened Vecna's reign so his disciples, barely more than a cult or clan at the time, rose to face the ursurper demons and ultimately slay them, banishing them back to their own hells.
Now, in the realm of
Azeroth, in the time beyond the burning crusade, another force of evil threatens overthrow the rule of the lich god. This new being, the combined essence of Arthas Menethil and Ner'zhul, has been released from its icy prison and attempts to rule the realm of Azeroth and then to use this realm as a staging point for its upstart plans for astral domination. Knowing there is no room in the astral planes for two lich gods, Vecna has again resurrected his chosen disciples to dispatch this false lich king and establish Azeroth as Vecna territory.
The lich god's holy symbol is an eye within the palm of an undead hand.
The holy symbol is branded on the skin of the disciple above the heart.
The tabard of the Vecna church is made of the rib bones of the disciple's first kill. This represents the chest of the lich god Vecna and his power through the undeath, thus his resurrection into eternity and the beginning stages of his godhood.