Kousuke in Naruto

Due to his reckless actions that cost him the lives of his teammates, Kosuke thought that he was not deserving of the title of a genin. Despite this, he trained hard to improve his skills and remained a genin for over fifty years, which earnt him the name of the Eternal Genin. Kosuke served the second, third and fourth Hokage throughout his lifetime.

He even fought alongside the Legendary Sannin, Konoha's White Fang, and the previous gen’s InoShikaCho trio. He was only one of the few people who knew that Naruto was Minato's son. He lost one of his legs in battle and replaced it with a prosthetic leg.

Six years after the Nine-Tails attack on Konoha, Kosuke was sent on a mission with Guy to complete the trading of secret scrolls with the Land of Woods to establish an alliance between the two villages. While they were on the mission, Guy noticed that this mission was actually to test the trustworthiness of the other village.

The guy was right as the Land of Woods betrayed Konoha after getting the scroll. As Kosuke and Guy were about to lose, Kakashi and Itachi (during their time with Anbu) came as a backup to save them and defeated the ninjas of the Land of Woods.

Seven years later he was put on a team with Hayama Shirakumo, Tekuno Kanden, and Naruto Uzumaki to guard the borders of the village after Orochimaru and Sunagakure attacked the village. When they were guarding the border they realized that their border was invaded by Iwa ninjas.

Kosuke directly clashed with their leader who mistook him for Konoha’s defense forces. Naruto came back as he couldn't leave his friend alone in the battle. Kosuke said that he wouldn't die and now he will let Konoha fall and with this defeat the Iwa Ninja.

He was then given a mission to retrieve valuable information from Iwagakure. After getting the information, Kosuke went back to Konoha immediately to give the information but he was trapped. He was then saved by Team Asuma.

Due to his knowledge and expertise, Kosuke is known for his calm, collected personality. He is seen smiling and hardly lets anything bother him even when he's on a mission. This usually portrays him as a lazy and uncaring person but in reality, he is quick to take action and has expert survival skills. He is usually carefree and can change in an instant to pure seriousness depending on the situation.

He is also quite loyal and believes in the Will of Fire and has a great sense of duty. This can be seen in his willingness to sacrifice himself for his comrades to escape and warn the village. He has little value in his own life due to what happened when he was a child and he always puts the village.

Kosuke is an elderly man who had black hair which has now turned grey and he wore it in a ponytail. He was measured with a sleeveless kimono and a pair of grey pants. He carries work that he uses for multiple things he also carries a ladle and a sword too. In his younger days, Kosuke had dark hair which was tied in a ponytail and he also wore a blue jacket with a mesh shirt underneath.

Kosuke is very good at taijutsu and a very skilled kenjutsu fighter. He wields a hidden blade that is concealed in this prosthetic left which he can use to strike with deadly precision. Despite his age, he is seen to be very agile and fast.

He uses a unique technique that uses genjutsu and kenjutsu together to confuse the confused and petrify his enemies which makes it easier to strike them down. He also learned the Shuriken Shadow clone technique from the third Hokage which he uses with a lot of proficiency.

He trained under the second Hokage and has a high caliber in water release techniques as he was even able to overpower Earth release. That was even though Earth is water's weakness. He can also use Earth-release techniques.

Kosuke Maruboshi vs Iwa ninja

Kosuke Maruboshi vs Pakura

Kosuke Maruboshi during Konoha Crush

1. "When you've been a genin for fifty years as I have, chances are you've worked with many who became great masters."
2. "There is no single Konoha shinobi who would sacrifice the lives of a genin!"
3. "You've left behind a fine son, Fourth Hokage."

Kosuke Maruboshi did not only appear in the series but also in a movie and video game.

Movies

Naruto the Movie: Blood Prison

Video Games

Kosuke Maruboshi is a playable character in the following video games:

Q. Is Kosuke still alive?

A. Yes, Kosuke is still alive and well in the series.

Q. When does Naruto meet Kosuke?

A. Naruto meets Kosuke in Episode 190.