I think that one of the Avatara must have been Ringo Starr. If you look closely you will see evidence that will point exactly in the direction of my theory. (With A Little Help From My Friends)-- maybe he means Alric.
Please, I know that I might be wrong and GURPS will probably have something pointing more in the direction of, say, Paul McCartney, but I don't think there is enough evidence. I mean while Paul McCartney had a very musical prestigous career following the post-Beatles era, Ringo was obviously dabbling in magical arts. The Myrkridia are ancestors of the Blue Meanies.
So before you go out and make a Beatles TC remember to consult Myth history.
-Darth Krid