The symbol from Erudin is definitely the Obelisk you can find in LFay which originally showed up in the Dead Hills. Both Bertoxx and the Envar/Prime Healer come from this area. My only question is which came first?
Both the Xolous and Envar were supremely powerful. Xolous was the only true enemy of dragons during the EQOA era.
Check out this link -
http://everquest.allakhazam.com/wiki/The_Crypt_of_Decay
Lots of things to connect here but the story becomes clearer every day.