You do indeed see much of Mayong Mistmoore...in the Plane of Hate.
Though several choose not to believe it, and it is indeed your choice to believe it or not, Mayong Mistmoore is the Maestro of Rancor.
Why do I say this? Well the first reason is because it is so. Second reason is because of the amounts of in game lore that point to it, including a GM event that involved Innoruuk, in a fit of rage, grabbing at Mistmoore and stating "You shall serve me for all eternity"...or at least something along these lines.
Mayong Mistmoore, as most of you know, has an undying love for music. He has pianos across his castle and has gypsies constantly playing music for him. It appears that this music is the only thing Mistmoore has left that brings him any kind of joy. Therefore, to torment him, Innoruuk is forcing him to compose and play music for him.
There are two people he hates more than anyone else across the planes and Norrath itself:
1) Innoruuk
and
2) Himself
He despises and wants Innoruuk dead more than anything, however his soul is now bound to the Dark Prince, and therefore he can only wish that Lanys T'Vyl will one day undo the "curse" he has.
This is why Mayong Mistmoore is no longer in the Castle, and this is why you no longer "see him".
