The Princess of Disaster is a being created when a Prétear has lost control of her emotions.
One former Prétear Takako became the princess of disaster when she allowed herself to be overcome with grief when her feelings for the Leafé Knight were not returned. She transformed into something other than a Prétear, something twisted and hateful. She was eventually sealed away inside a tree in Leafenia, but not without the sacrifice of three of the knights. Fifteen years after that she was able to break the seal, escape, and summon an army of Demons.
- In both the manga and the anime, Takako became the Princess of Disaster when she lost control of her emotions. However, in the Manga she chose another person to act as a 'host' even as her body was still sealed away. In the Anime, she managed to break the seal, escape, and act on her own.
- It is not entirely clear if only a Prétear can become a Princess of Disaster, or if anyone can. It was implied that there had been at least one other before Takako.