I have never seen Despero battle on the astral plane, but since he has telepathic abilities, I thought that he would possess or manifest some sort of non corporeal form. I'm sure that he can do this because he has battled Jonn Jonnz's mind several times. The question here is does anyone think that he would have a chance in hell against the Shadow King in his realm?
Shadow King nearly devoured Xavier on the Astral Plane, if it wasn't for Jean he would have. Even with her help he broke Xavier's legs in the physical realm.
__________________ "damn jinzin, you're a real trooper, you provde fact after fact and pages and pages of proof and these wanton miscreants just keep at it"~MERC
You are right and wrong, Xavier beat the Shadow King in their first encounter, but was nearly killed in their second encounter. Shadow King is vastly superior to Xavier these days. I can't remember what X-Factor comic it happened in because the bulk of my collection are in another country. perhaps someone else knows the book that I'm refering to.
As far as I know, there is only one Shadow King. My personal favorite was when he showed up in New Excalibur wearing an alternate Earth Professor Xavier as his host. Dark Xavier x2!
But I digress, Despero is out of his depth in this battle. Shadow King wins.