Alioth does have a titled ancestor, known as Reckoner Glacious. (He was from the early conquest era.) He was untitled for a long portion of his life, going by Delwyn Ghelda instead. He was a court official and king's mage, offering guidance and protection for the royal bloodline of the nation he had hailed from. Had seen and studied much, and often tutored other nobles.
However. Delwyn had many peers who were jealous of his position and fame- and felt scorned by his seeming indifference to the station of said peers. (He was held in high enough regard that he could get away with being "rude" (read: not sucking up) to some influential trolls.)
A group of conspirators ended up framing Delwyn for treason, and the gruesome murder of a prince. He fled these accusations, and his home- eventually returning with a plan of revenge in mind. He would tear down the old rule, killing numerous rivals and destroying the royal line of the kingdom.
He was rumored to consort with demons. That he *was* a demon himself. Patient, persistent, and ruthless. Anyone that got in his way was not spared.
And then, when his revenge was through, he disappeared.