Koheita Nanamatsu is a sixth-year student at the Ninjutsu Academy in the anime film Gekijо̄-ban Nintama Rantaro Dokutake Ninja-tai Saikyо̄ no Gunshi. He belongs to the sixth-year ro class and holds the position of chairman of the Sports Committee, a role that matches his immense physical energy. He is the eldest of eight siblings. His personality is defined by an overwhelming and relentless positivity. He approaches most situations with a booming laugh and his characteristic cries of not sweating the small stuff and letting things go. This infectious enthusiasm means he often acts on impulse, but it is paired with a surprising perceptiveness and a genuine desire to help. In the film, the disappearance of the homeroom teacher Doi-sensei prompts the academy to act. Koheita joins his fellow sixth-year students in investigating the mystery, which leads them to a direct confrontation with the antagonist Tenki. He participates actively in this battle, demonstrating the bravery and combat skill expected of a senior student. His closest relationships are within his peer group. He is particularly close with Monjirou Shioe and Chouji Nakazaike, with whom he frequently trains and takes on part-time jobs. His expressive demeanor contrasts with the silent Chouji Nakazaike, for whom he often serves as a translator. As the Sports Committee chairman, he is a lively and demanding mentor to his juniors. The film showcases his development from a purely fun-loving source of energy into a reliable and formidable upperclassman. His defining trait is his incredible physical stamina, allowing him to dig trenches with his signature kunai. He is highly skilled with dual-wielded kunai and has a noticeable habit of reflexively spiking any object sent his way.