Ellie Craft is the English-dubbed name for the character originally known as Onpu Segawa in the Japanese version of Magical DoReMi. In her first appearance, she is introduced as a famous and highly popular child actress and idol who transfers to the same class as the main characters. Due to her celebrity status, she is immediately recognizable to her peers and is often the center of attention at school.

Her personality initially comes across as calm, reserved, and somewhat distant. Unlike the more energetic and expressive main characters, Ellie often displays a cool and collected demeanor, showing little obvious emotion. Beneath this composed surface, however, she is highly ambitious and determined, particularly regarding her career as an entertainer and her goals as a witch. In the beginning of the series, she can be quite sneaky and manipulative, using her charms and position to achieve her objectives, which puts her at odds with the other apprentice witches.

Ellie's role in the story is defined by her status as a rival to the lead character, Dorie. This rivalry stems from the magical world, as Ellie is an apprentice to Majo Ruka, a witch who is the rival of Dorie's own teacher, Patina. Their initial relationship is one of conflict and competition, as they are on opposing sides of a magical disagreement. A key part of her motivation is tied to her magical training; at one point, she uses forbidden magic to erase people's memories in an attempt to protect her group from suffering her mentor's fate, demonstrating a deep-seated loyalty and a willingness to sacrifice her own standing for others.

As the series progresses, Ellie undergoes significant character development. The initial hostility between her and the main group of witches slowly fades, and they eventually become close friends who fight alongside each other. She reveals more of her vulnerabilities and comes to value friendship over rivalry. Her relationships evolve from sneaky competition to genuine camaraderie, integrating her fully into the central circle of friends.

As a magical girl, Ellie possesses standard witch abilities, including spell-casting and the use of magical artifacts. Her notable magical abilities include the use of banned magic, a powerful and forbidden type of spell that carries severe consequences for the user. In her civilian life, her notable abilities are tied to her profession; she is a talented performer, singer, and actress who appears in numerous television shows and films, making her a recognizable public figure within the story's world.