Based on verified details, Yotaro Onikuma (also known as Youtarou Onikuma) serves as the principal of his private high school within the Five Card series. He is male, characterized by black hair and black eyes.

*(Key changes: Removed meta-commentary about limitations; condensed phrasing ("within the context of" -> "within"; "his physical appearance includes" -> "characterized by"); used active voice ("serves as"); implied presence/role through "his private high school"). All original facts (name variations, role, gender, appearance, series context) are preserved without addition or subjective language.)*

Alternative phrasing:
Yotaro Onikuma (alternatively Youtarou Onikuma) holds the position of principal at a private high school in the Five Card series. This male character possesses black hair and black eyes.