Leo is the protagonist Elorie's little brother and a crucial part of her life, as she is his only family. He's an six-year-old boy who loves tigers and is both smart and classy. Leo cares deeply about his sister's happiness, though he doesn't fully grasp the concepts of mental health or relationships. 

He has a very soft, slightly high-pitched voice, typical of an eight-year-old child. Despite being a supporting character, Leo appears frequently throughout the series.