The Troll Hall Chronicles
Mind flayer nemesis of Kane Karrath
Xzathral is the the illithid Kane Karrath was pursuing when the two were transported into the Pyramid of Shadows, trapping them both. At some point he was changed into a horrifying monstrosity that looked more like a beating, weeping organ in a Far Realm-warped corner of the pyramid. He was ultimately destroyed by Vicendak, who claimed the illithid’s brilliant amulet for himself.