Character: shadow queen
The true main antagonist of Paper Mario: The Thousand-Year Door, the Shadow Queen is a powerful demonic witch responsible for the destruction of ancient Rogueport and the creation of the Crystal Stars. Sealed away 1,000 years ago by four heroes with the power of her own Crystal Stars, the X-Nauts seek to resurrect her in order to conquer the world. Her servants are the Three Shadows (Shadow Sirens in the original North American GameCube version). Her unsealing was engineered by Beldam, who manipulated Mario and the X-Nauts into gathering the Crystal Stars and opening the Thousand-Year Door to resurrect her master.
In the form she takes after being unsealed, she is a large, vaguely humanoid purple figure similar to the Three Shadows, with stars throughout her body and long, dark hair adorned with a tall crown on her head. Upon possessing Princess Peach, Peach's body and clothing changes to accommodate its new host and she becomes Shadow Queen (Peach). When manifesting her true form, her body coils around Peach like a cage, while her head floats above Peach and her hands appear from the floor on both sides of her body.