Leon Sensei is a Legend Fairilu born from a chameleon, and he serves as a teacher at Saint Fairilu School. He primarily instructs students in the art of shapeshifting, helping them learn to transform into their human-like forms. In appearance, he is often seen as a tall, beautiful woman with long blonde hair and yellow eyes, though his true form has never been revealed to the students, and the ambiguity of his appearance has been a topic of curiosity. His personality is notably self-expressive; he embraces his own unique style and encourages his students to express themselves in their own ways as well. He believes in individuality and uses his flamboyant demeanor to put pupils at ease during lessons. His role in the story is that of a supportive faculty member who provides instruction and occasional guidance to the main cast, especially during episodes focused on learning new magical abilities. He appears in both the first season, Rilu Rilu Fairilu: Yousei no Door, and the second season, Rilu Rilu Fairilu: Mahou no Kagami, as a supporting character who helps the young fairies grow in confidence and skill. While he does not undergo major personal development within the narrative, his consistent presence reinforces the importance of self-acceptance and creative expression. His key relationships are with the student fairies, such as Lip and her friends, whom he teaches and occasionally advises. His notable ability is his mastery of shapeshifting magic, which he uses both to demonstrate transformations and to assist students in mastering their own human forms.