The Sovereign are the supposed chosen of the Wheel, the conduit of the Wheel’s Meta and the keepers of the afterlives.
There are zero to three Sovereign in current times, depending on who you ask. There is The Somnolent, who is always in the public eye, Sigsalm who is well known and makes appearances from time to time, and Euphraeasthi, who has not been seen for thousands of years and who many believe to be dead.
They're just Monoliths, if you ask me. Oh yeah, sure, whatever, they're powerful an' all, but they're con artists sayin' they're more powerfull 'n they really are, y'know?