this worked for me but it may hav just been a bug, it doesnt get u any xp but u finish the quest
when you first go in to the planar sphere save in the room just before you get teleported. go in and you'll get taken to the other plane. get killed by a monster and reload. I didnt get anything special for it but everyone talked as though id finished it
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Nor shadow or myst
the jester is a myth
he is absolute
beware the jester