Might Duy

, often referred to as the, was a shinobi of Konohagakure.

Background
Duy spent his entire career as a genin, causing many to look down upon him and earned him the epithet of the. Despite this, after twenty years of tireless training, Duy perfected how to use all Eight Gates. He later had a son, Guy, who showed little progress as a shinobi himself, failing his first attempt to enter the Academy. When Guy began feeling sorry for himself, Duy scolded him for not having faith, and ultimately taught Guy how to use the Eight Gates. One day, he and Guy met Sakumo Hatake and his son Kakashi in front of the Academy; Sakumo assumed their sons would be classmates, only to learn that Guy flunked the entrance exam.

Some time after that, Duy rescued his son and his teammates, Ebisu and Genma Shiranui from the Seven Ninja Swordsmen of the Mist who had confronted the trio. Though his son argued that he was no match for the Kirigakure-nin, Duy reminded his son that he still had the Eight Gates technique and would use it under the very same condition of use he created — the protection of someone precious to him. In the anime, Duy's efforts ultimately killed four members of the famous group. It can be inferred that the 3 surviving members of the encounter were Jūzō Biwa, Fuguki Suikazan and Raiga Kurosuki due to the fact that the three met their ends by other means.

Personality
Duy was a proud and upbeat man. Like his son, he was overzealous, regularly using a "nice guy" pose, thanking people who were otherwise chiding him for his behaviour, or low rank. He believed strongly that one must have confidence in themselves in order to achieve anything. He also believed that one's true youth only ends when one turns their back on their beliefs and joy. Duy had a very strong relationship to his son, constantly pushing Guy to be his best and lifting his spirits when upset; a relationship that is parallel to Guy and his disciple, Rock Lee. A committed man, he had no fear in facing his enemies, nor in sacrificing his life for Guy's sake. Duy would pass on to Guy the belief that the truest expression of strength was not defeating a powerful opponent, but defending the ones he loved.

Appearance
Duy was a tall and well-built man with high cheek-bones, a somewhat bulbous nose, dark hair, thick eyebrows and noticeable body hair on his wrists and forearms. His hair was cut in a bowl style that was combed to his right and lifts slightly. He also sported a bristling moustache with a small goatee and stubble which made up the rest of his beard. He wore a green jumpsuit, orange striped leg warmers, and a yellow scarf around his neck.

Abilities
In the anime, it was said that Might Duy wasn't able to use both ninjutsu and genjutsu. He was also failing simple missions. It was revealed his poor performance was due to him secretly training with the Eight Gates every night, which has a common side effect of weakening the user for a prolonged period of time.

Taijutsu
Despite being genin-ranked, Duy possessed great physical condition and prowess in taijutsu, allowing him to open all Eight Gates, although he spent twenty years mastering it.

While admitting to it being his only achievement, Duy was competent enough with his abilities to teach the kinjutsu to his son and later using it to fend off the entire Seven Ninja Swordsmen of the Mist and (in the anime) kill four of its members.

Legacy
Duy's sacrifice left a huge impression on Guy. He continued his father's belief of maintaining one's youth as well as to persevere for a cause. Guy also formed a similar relationship with his student Rock Lee, as he did with his father, yet in reversed roles. Eventually, Rock Lee would pass on Might Duy's belief to his own son, Metal Lee.

Trivia

 * Duy's epithet is one he shares with Kosuke Maruboshi.
 * Duy's full name is a pun on the phrase, "Might Die", which is tragically foreshadowing considering he actually ends up dying after opening all Eight Gates.
 * Duy was most likely made to honour Kishimoto's father, who passed away around the time when the only chapter featuring Duy was released.
 * Duy shares the same voice actor in both English and Japanese of the anime with Guy.

Quotes

 * (To Guy) "You know what a true victory is? It's not beating someone strong. It's being able to protect something important to you!"