Tsujiai is a classmate of Kaji Ayu and Nina. He is the head of the male tennis club and is a slightly extravagant person. Ayu seems to hate him because at the start he always managed to destroy her chances with Kaji one way or another. Tsujiai introduces Nina to Doraemon which she loves. His best friend is Kaji and he likes Nina which is shown more in the manga than in the anime. He has a cat name Shinnosuke and is the second person to know that Nina was a magic girl because he saw that Rio the cat transforms into a human.