The Masked Lady, known as Celia, appears as a mysterious figure inhabiting the story's castle. She wears a plain white mask and cloak, often floating or hovering with ghost-like qualities, including the ability to turn translucent. A pocket watch hangs around her neck beneath her cloak. Initially, she treats the Little Girl with cold disapproval, frequently questioning the worth of playing piano with Deemo and claiming the castle was more peaceful before the girl's arrival. She expresses strong disdain for their efforts to grow the magical tree, crushing a fallen leaf in one scene. When the tree reaches 20 meters, her dialogue shifts while remaining antagonistic. She actively prevents the Little Girl from opening the door to the Top Floor, physically struggling with her until Deemo intervenes. Celia originated as an aspect of Alice's personality. After Alice and her brother Hans suffered a fatal accident where Hans shielded Alice with his body, Celia manifested in the dream world as the part of Alice unwilling to accept her brother's death. She awoke in the castle first, before the Little Girl and Deemo existed there, experiencing amnesia within a realistic construct of her home. By playing piano songs, she obtained a white cloak and mask pieces. An embellishment on the cloak revealed her name as Celia, an anagram of Alice. Upon assembling the mask, she regained her memories and faced a choice: wearing it symbolized willful ignorance of reality, cementing her role as the Masked Lady in the main story. Destroying it would have caused her to awaken as Alice in the hospital. Her true identity emerges when the Little Girl realizes Deemo represents Hans. The Masked Lady then removes her mask, confirming she embodies the part of Alice resisting awakening. In later "Forgotten Hourglass" playthroughs, her demeanor softens significantly. Residing in the Mask Room between playthroughs, she awaits the Little Girl's return and converses directly with her. Their interactions evolve from changed dialogue to reconciliation, with the Little Girl apologizing for causing Celia's silent suffering. Celia expresses hope that both aspects of Alice will one day accept each other as parts of a whole.