Maruo is characterized by his strict and no-nonsense demeanor, presenting himself as a disciplined and responsible man who takes his role as a father and provider very seriously. He is a workaholic who often spends long hours at the office and expects strong results and dedication from his daughters in return.

Although he can appear cold and distant, and his relationship with his daughters can be strained, it becomes clear that he cares deeply for their well-being. His decisions, while sometimes harsh, are driven by a desire to secure their future. Maruo rarely expresses his emotions openly, but his actions consistently show his devotion, revealing that he is willing to make personal sacrifices for the sake of his family.

Maruo Nakano is intelligent, disciplined, and highly professional. He works as a successful doctor and businessman, handling medical and administrative duties with precision. His strict, detail-focused mindset helps him make important decisions, especially when it comes to the quintuplets’ education and well-being.

He is also good at maintaining order at home and enforcing discipline when needed. Despite his stern appearance, Maruo shows emotional strength, dedication, and a strong sense of responsibility, always putting his family first.