Sheoldred, known as the Whispering One was the Praetor of the Black Faction of New Phyrexia. In the year 4562 AR, she led an invasion of the plane of Dominaria, where she attained several important military objectives in preparation for New Phyrexia's Invasion of the Multiverse. After her return to New Phyrexia, however, she lost a power struggle against the Mother of Machines, Elesh Norn. Sheoldred was subsequently captured by Norn's forces and beheaded by Ajani Goldmane.
https://mtg.fandom.com/wiki/Sheoldred