U-1

U-1, pronounced as Yūichi (ユウイチ) in Japanese, is the main protagonist and title character in Gitaroo-Man. He is voiced by Lenne Hardt in the English port and by Yuka Imai in the Japanese version.

He comes from a normal white-collar family and is an elementary school student by the time the story begins. U-1 is a clumsy Average Joe who is considered to be a loser by his classmate Kazuya. He wants to spend his summer vacation practicing his skateboarding skills to impress Pico. While he wants to someday oust Kazuya, he lacks the confidence to do so and sometimes believes in Kazuya's words.

What U-1 doesn't know is that he inherited the blood of the legendary Gitaroo-Man and wields the legendary Gitaroo, a guitar-type weapon that changes him into a soldier of Planet Gitaroo. As soon as the Gravillian Empire learns that the last Gitraoo is located on earth, various Gravallian soldiers try to steal it away from him. To defend himself, Puma and his back up band teach him how to use the Gitaroo. U-1, being a natural at the art, unwittingly collects his rival's Gitaroos. After defeating his third opponent, Elder Miranda sends U-1 a digital transmission from Puma's eyes, begging the boy to save him and the other Gitarians. Without much ado, Puma forces both of them inside a spaceship (called the Woofer-Jet) and, through U-1's complaints, they head for Planet Gitaroo. While they stop at a space satellite, Zowie introduces himself to U-1 and the boy refuses to hand over his Gitaroo since Zowie reminds him of Kazuya. After they crash land on Planet Gitaroo, U-1 finds an acoustic guitar and plays a song for Kirah, who looks a lot like Pico.

When Puma is kidnapped the following morning, U-1 personally gains the strength to rescue his friend and faces the Sanbone Trio without his Gitaroo. When Puma is freed, he proudly stands as Gitaroo-Man once more and saves the imprisoned Gitarians. Elder Miranda tells him that he only has two more Gitaroos to collect for the ultimate Gitaroo. After Gregorio's defeat, Zowie stages the last fight for U-1 at Gitaroo Arena. His unlikely opponent is Kirah who is intent on fighting him. U-1 can't bring himself to fight her and realizes that his true enemy is Zowie. He ignores her aggressive rifts and plays the legendary song of Planet Gitaroo. The moving performance makes Kirah realize that her music can be used for more than fighting, and she gives her Gitaroo to U-1. With all eight Gitaroos, U-1 is considered a hero by the Gitarians.

Zowie scolds Kirah's change of heart and belittles U-1 in the same manner as Kazuya, saying that the boy couldn't even beat him in "an never-ending eternity". U-1 snaps at the remark and finds the confidence that he needs to unlock his Gitraoo's ultimate form. Blasting Zowie away in space, Puma catches him in the Woofer Jet and they head back to earth, despite U-1's pleas to return to Planet Gitaroo.

Based on Pico's comments, the entire trip was U-1's summer vacation. When Kazuya tries to insult U-1 again, U-1 finally stands up against his classmate and happily runs away with Pico.