So there were a bunch of Ultraverse crossovers in 1995 and 1996 that I’m not covering because I don’t think they’re canon–even though the framing sequence for this one-shot starts with Sersi and Black Knight leaving the Ultraverse.
Instead of returning to the 616, though, they end up in 12th Century, each occupying the body of a person in that era.
There, they meet Exodus and Apocalypse.
Hilarity ensues.
The point of this comic seems to be to tell the origin of Exodus, but the Sersi/Black Knight stuff just brings it down.