He has an easy-going personality and a bright disposition, along with a frank and direct attitude, which often gets him into heated arguments with Chiba Erika. He's also someone who can be easily persuaded, and motivated to do favors. Sometimes, he can be clueless and ignorant in a certain way. He is quite a courageous and a hot-blooded person. However, as a descendant of a Fortress Series Magician, Leo also carries a deep fear of going insane and dying early, as many of the first generation test subjects did. In an effort to avoid this, Leo tries to follow his impulses, such as roaming at night like his grandfather, who lived a natural life span.