Mannimarco, also known as The King of Worms, was a male Altmer and is the head of The Necromancers. Very little is known about him, or the motives he is driven by, beside the fact that he has lived for a very long time, perhaps over a thousand years. He is in league with Princess Morgiah of Wayrest, because she needs his influence on the dead to gain influence over her further husband the king of Firsthold on Sumerset Isle. In return she promised him her "first", though it is not clear what this means. Due to his high age and dark magic, he has knowledge of things that very few mortals know of. He knows for example, that Prince Karolis, the great grandfather of Camaron, late king of Sentinel, roams the deeps of Palace Sentinel as a lich. This is one of numerous secrets of the royal dynasty of Sentinel. He also knows the true identity of The Underking and has been in a struggle for power with him for many centuries. Mannimarco has also very little love left for the Mages Guild or the Septim Empire.
For more information, see the Lore article on Mannimarco.