Exodus

Exodus was a villain, the spawn of Mondain and Minax.

He was based out of Ilshenar, in a dungeon in the central region of that facet. His meddling in the timeline of Ilshenar caused the official fiction of that facet to change. He was behind the invasions of certain cities by the Juka.

He was never seen in-game, but was said at one point by Dawn to have simply faded away and died.

Traditional Ultima lore holds that Exodus was a sentient computer of some kind.

UOStuff

In Ultima Online, the plotline was similar.

Exodus was a machine entity of some kind spawned by Minax and Mondain. The evil machine's sins include altering the timeline of Ilshenar to upset the balance between the ancient Ilshenarian races of Juka and Meer, converting Lord Blackthorn from Chaos to full-fledged evil, and, with Blackthorn, using the Juka to launch attacks against Britannia.

According to Dawn, a "Royal Knight" of the realm, Exodus died around the time of the Age of Shadows expansion, just before Blackthorn launched a doomed but destructive assault on the city of Yew.