A young boy who is overweight and has few friends, frequently tells lies. When someone tries to steal Nagatsukas bike, Ishida offers his own in exchange. Nagatsuka sees this act of selflessness as a strong bond between them and quickly declares Ishida to be his best friend. He becomes extremely devoted and protective of Ishida and often disapproves when Ishida interacts with other people. Despite this, Nagatsuka is also supportive and provides advice to Ishida. His ultimate goal is to become a millionaire, so he generously gives money to friends and aspires to be a film director-entering himself and Ishida into a movie competition. Both Ueno and Kawai find Nagatsuka unpleasant, while Ishida feels uncomfortable about his eagerness to take Ishidas side despite not knowing much about him. Although their film fails, this only motivates Nagatsuka to pursue film studies as his college major.