An elven lich, imprisoned in a snare in the city of Ostpadash in IY 442. His phylactery later came into the possession of Luthtor the Drunk. Under its influence, Luthtor attempted to open the snare but was unsuccessful.
From the reports of Imperial Eighth Seeker Vestra Splitter-of-Bones
17th day of summer, 442nd Year of the Imperial Age: We managed to track Nathoris Skybane back to his ritual chamber and confine him. Unfortunately, his phylactory could not be located; instead we trapped him in a Snare. Without final destruction, there are no guarantees, but the Snare key is very specific and costly; any attempt to use it will certainly draw attention. So that it is not forgotten, I record it here: the death of one, buried alive; then two, by drowning; then three, by flame; then four, bled dry at dusk. Should it be completed, Nathoris will be freed at the full moon.