Natsumi is a hardworking, dedicated, and responsible perfectionist. He is seen as a role model due to his kind, caring, and selfless nature. He is very handsome and sporty, being the best swimmer in his school's swim club and an excellent student. He enjoys simple things like ice pops, doing chores, swimming, and collecting beetles. Despite his competent exterior, Natsumi is an overthinker who gets anxious and worried when things go wrong, driven by a desire to be useful. He isn't tech-savvy and looks up to his older brother, Naoto, but feels immense pressure from being constantly compared to him.