It's Complicated

Ato Touji is a young man just starting his last year of high school. Of course, that high school is the Onmyo Preparatory School and he is studying to become an Onmyo exocist. He is tall and lanky, as well as calm, cool, and collected. He tends to dress casually, in what might called a grunge or street fashion, and is often wearing a head scarf. He is also likely to be wearing a school uniform over his more relaxed attire, thought the headband is always present.

If your character can see into someone's spirit or soul: Touji is infected with the essence of an Oni. This essence his bound by a talented Onmyo doctor and so may not be noticeable. Fellow Onmyo initiates and novices saw nothing amiss with Touji and even a high level, free lance Onmyo exorcist didn't notice anything was off until the binding started to slip.

If you're character is telepathic or empathic, they may pick up stray thoughts of violence or cruelty that seem congruent to Touji's facade. This is the oni essence's presence and not Touji, though this may not be apparent.