Herriot is a female dragonoid character in the Puzzle & Dragons X anime, known for her role as the current Ancient of Light. She has a fierce and proud demeanor, combined with an energetic and strong personality that defines her as a formidable Dragon Caller. Her appearance is striking: she has yellow hair and possesses heterochromatic eyes, with a violet left eye and a yellow right eye. A light-yellow wing extends from her back, emphasizing her dragonoid heritage.

Her background is tied to a childhood separation from her younger sister, Morgan, who would later become the Ancient of Dark. The two were happy together until Herriot was taken away by a character named Jest. This event forced the sisters apart for many years, but Herriot grew up to become a strong and energetic warrior. A significant part of her personal story involves the eventual reunion with Morgan after their long separation.

Herriot's primary role in the story is as a mentor and teacher to other Dragon Callers and dragonoids, including the characters Garnet and Ace. Her motivation is deeply rooted in her responsibilities as the Ancient of Light and her desire to guide the next generation. Her key relationship is with her younger sister, Morgan, and the emotional arc of their separation and reunion is a central aspect of her character. Her notable abilities stem from her status as the Ancient of Light, though specific power details are not provided in the available information.