The surfaceless dungeon

After exploring the two hundred sub-levels of the Dungeon of the Sun Serpent, a black mage turned lich and having lost all her companions, managed to defeat the creature on the final floor. After accomplishing this feat, she realizes that she has spent so much time in the depths of the dungeon that she has forgotten her age and name. With nothing left to prove that she was once human and knowing that she has long accepted her status as a lich, she now considers herself a full-fledged monster of the dungeon. One day, while walking on the floor to find something to do with her life, she steps on a trap that shoots her with a cursed arrow. She rushes to the one hundred ninety-eighth sub-level to find herbs to heal herself. But as she sets about the task, she encounters a harmless dryad who offers to heal her if the lich helps her traverse the dungeon floors to discover the outside world.