|Age|| Over 200 years|
|Occupation|| Muse of Protection|
|Residence|| Castle Heterodyne|
|First Appearance|| and |
|Relatives||Two (known) remaining "sisters," Moxana and Tinka; other Muses presumed destroyed|
Originally, Otilia was one of Van Rijn’s nine Muses, built for the Storm King. She is referred to as the Muse of Protection. Otilia has frames for wings, which would make her the muse in the center top of the fresco.
At some point prior to the attack on Castle Heterodyne, Lucrezia Mongfish transferred Otilia's consciousness into a fleshly body, creating the construct Von Pinn. Lucrezia also transferred (a part or copy of) the Castle Heterodyne consciousness into the Otilia body.
This Castle/Otilia was being kept in chains in the extensive basements of the Castle several layers below the great movement chamber. When Agatha shut down the Castle’s AI, she announced herself as being “Free!” to the main cast, many layers above.
When Otilia is first ‘freed,’ she hears the voice of Lucrezia, whom she declares to be a traitor to the House of Heterodyne. . Determined to get to her, she ascends the basement levels by means of the giant hole Agatha shot into the Castle with her death ray. Otilia’s demeanor promises pain when she reaches Lucrezia, who, unfortunately, is only present by means of possessing Agatha.
She is prevented from hurting Lucrezia/Agatha by Tarvek, who attempts to control Otilia by revealing to her that he is the current Storm King.. This does not end well, revealing that, unlike Tinka or Moxana, she does not acknowledge Tarvek as her leader. The reasons for this become clear when it is revealed . It was thought that all fragments of the Castle’s personality were destroyed by Fra Pelagatti's Lion. Obviously, however, this is not the case. The castle's AI came to be housed in Otilia's body because of the experiments of Lucrezia, it doesn't appreciate it much. 
Tarvek and Otilia/Castle begin to fight, and the former muse shows great physical prowess, far more, actually, than historic accounts indicated.  As they fight, Otilia/Castle loses more and more of her mental faculties, having problems speaking. She appears to be about to triumph over Tarvek, . Zeetha fights briefly with her, and then The Unstoppable Higgs is told to .
Higgs reveals that he has knowledge of at least the basics of Otilia’s construction, making comments about her condition as she attempts to fight with him although this could just be banter. He avoids her blows, but she finally manages . His ability to withstand this blow causes Otilia/Castle to recognize him. Just as she is remembering who he is, he smashes her with a wrench.  Later she and Higgs collaborate to test Agatha.
Von Pinn later refers to Otilia as "Lucrezia that even in her current form, she is still the muse of protection.", indicating that she is Otilia's original personality. This is further reinforced later when she claims to