During life, he was a mage and necromancer of the Kirin Tor in Dalaran, and a friend of Bethor Iceshard and Thule Ravenclaw. Sometime during the Third War, he was killed and raised as an undead slave to the Scourge. Gunther was a powerful mage in life, and still strong in undeath, as he managed to break free of the Lich King's control of his own accord. Thinking he was the only undead with free will, he distrusted all others and retreated to Gunther's Retreat for several years, but agents of the Forsaken proved to him that there were undead who fought the Scourge too. Gunther then joined the Forsaken, reunited with his old friend Bethor.
Although his appearance is that of a usual undead, he is powerful enough to be called a Lich by the Forsaken.
He starts the following quests:
- It has been a long time, Bethor, my friend.
- When time permits, we must speak at length. For we have much to discuss.
- And thank you, <Name>. Without your aid I may never have found my way to the Forsaken.
Though he is referred to by the title of "lich", he actually isn't one: he gained the title from other members of the Forsaken due to his sheer power.
He could possibly be brought in as a reason to add a Necromancer class to the game.
It isn't explained anywhere throughout his quests whether he knew Necromancy during his time in the Kirin Tor, which would have been "Illegal", or if he learnt it after being reincarnated.
His level is unreasonably high for the zone he is in, though this could simply have been added for the 'fantasy' of his power, rather than anything else.