WMG / Grand Unifying Guesses Book Of Amber

Every setting in every work of fiction is a shadow of Amber. The following people are secretly Corwin, with or without amnesia:

The Old Kingdom series is actually just a shadow of Amber
The old kingdom is actually part of a shadow which was being devoured by the black road, like Corwin's Avalon. However, through the extensive use of Charter magic (a shadow of the Pattern), it was possible to create the Wall, which doesn't keep the Old Kingdom and the Southerners separate so much as keep the boundary between their universes constant. The events of the series are an analogue of the Fisher King events of the first half of the Chronicles, with most of the main characters being shadows of Amber Royalty. A particularly obvious instance is Kerrigor, who's basically Brand with a bad haircut. "Free Magic" is obviously as shadow of the Logrus, and Sendings are basically lesser versions of Pattern Ghosts.

Aslan and Tash are really another incarnations of the Unicorn and the Serpent
Narnia is of course another shadow of Amber.

All Merlins in fiction are shadows of Merlin

Getta Energy and Spiral Power are forms of energy created by the Logrus and inserted into worlds controlled by the Pattern
Uncontrolled they will either give those worlds to Chaos or destroy them. Either way, the Logrus wins.