Quote Originally Posted by Psyren View Post
As I mentioned above, there is not just one "Xanathar." The current bearer of the title is childish because they are a young Beholder, hence the caliber of the sidebar jokes in XGtE.

Mark might have been thinking of Kirukeskai, the most famous crime boss 'Xanathar' throughout 3rd edition, or its predecessor the original Xanathar (which might have been that creature's name) who was secretly slain back in 2e.
TBH, I don't care who the Xanathar was. I just thought the writing was boring.