Ryou is a genius from a wealthy family. In episode 36, his father mentions that his IQ was over 180 at age of 10. He is headstrong, stubborn, rude, sarcastic, and occasionally reclusive.

He takes his work in the Mew Project very seriously, even testing the project genes on himself in order to ensure its safety. He's particularly rude to Ichigo, often teasing her and getting into fights. But despite his abrasive attitude he has a caring side, inviting the girls on trips, and being willing to risk himself in battles despite having no powers of his own. He often comes to Ichigo's rescue whenever she is stuck in her cat form and is kind toward Retasu, encouraging her to be more confident in herself.