Iwao Oguro

Mr. Oguro (雄黒) is the vigilante known as Knuckleduster.

Appearance
Knuckleduster is a towering, heavily muscled man. What is visible of his face under his mask reveals heavy stubble and part of a scar on his left cheek. His costume consists of a simple wrap-around mask tied over the top of his head, a tight-fitting dark shirt, jeans, boots, a trench coat, and a pair of gloves topped with a pair of brass knuckles, or knuckledusters, from which he derives his name.

Personality
Despite his intimidating appearance, Knuckleduster is actually a very caring and good-hearted individual with a drive to do the right thing. Despite having no government-issued hero license, he still puts on his costume and goes out every night to fight street-level criminals and local gangs to keep his neighborhood safe from crimes most "heroes" will not bother with.

He appears to enjoy a challenge and becomes very upset or frustrated whenever there are no particularly strong Villains to fight. when a fight is too easy, he quickly becomes depressed. He also prefers to punch first and ask questions later, as he is willing to beat up people he deems to look suspicious on the slim chance that they may be villains or users of the Trigger drug. His attitude extends that he was willing to attack a defenseless young-appearing woman who had a Hero Provisional license, and felt little to no guilt or worry about doing so, despite the fact that he could have been registered as a Villain if the misunderstanding continued, showing a more aloof and careless side to his personality.

Despite having no Quirk, he shows no resentment towards people who do and shows no fear towards Villains who have powerful Quirks. In fact, he seems to enjoy fighting against particularly strong people who have powerful Quirks. This seems to be one of the main joys of his life, as he becomes invigorated whenever he gets to fight a strong opponent. He is even willing to fight against professional Heroes if the situation calls for it. Despite this reckless streak, he does genuinely admire Heroes for the work they do, and it is hinted that he would like to be a Hero himself, despite not having a Quirk, hence his Vigilante work.

Synopsis
While looking for the Trigger drug, he encounters Pop Step and Crawler and saves them from Soga Kugizaki and his gang. The three begin working together as vigilantes in the East Naruhata neighborhood.

Strengths and Abilities
Overall Abilities: Knuckleduster is Quirkless, proven when Shouta Aizawa tried to erase his Quirk only to have no effect on Knuckleduster. Despite being Quirkless, Knuckleduster is incredibly tough in strength and skill as he was able to fight on even terms with Shouta. He was also able to single-handily defeat Stendhal with a single blow.

Hand to Hand Combat: Knuckleduster appears to be skilled in hand-to-hand combat utilizing brass knuckles as his weapon of choice. His skill with his fists was great enough to overcome Chizome's skill with the sword, landing a heavy blow before Chizome could scratch him.

High Durability: Despite being Quirkless, Knuckleduster is very sturdy, standing up even when he receives blows from physical enhancement Quirks.

Heightened Strength: Knuckleduster's strength is surprisingly high, as he is sometimes mistaken for having a strength enhancing Quirk.

Equipment

 * Grappling Hook: Knuckleduster has been seen swinging from buildings with a grappling hook.

Mrs. Oguro
Knuckleduster's wife appears to be bedridden and may be stricken with a terminal illness that has ravaged her body. Knuckleduster appears to love his wife very much and to be remorseful over their difficult past. As she is unable to speak due to her illness, it is uncertain how she feels about her husband.

Koichi Haimawari
The two vigilantes share a loose teacher-student relationship, with Knuckleduster helping Koichi with combat training and initially helping him use his quirk more effectively. It was Knuckleduster that suggested that Koichi change his hero name to The Crawler and pushed him to take his role as a vigilante. Despite this, the two are not especially close, with Koichi being generally terrified of Knuckleduster's predilection towards violence. However, unlike Kazuho, Koichi is able to acknowledge that although his methods are rough and seemingly excessive, Knuckleduster knows when to hold back when it comes to the force of his attacks, showing a respect for his skills as a vigilante.

Kazuho Haneyama
The two are fellow vigilantes, but their relationship can be deemed as a rocky one as both tend to bicker with one another on more than one occasion. Kazuho does not appear to tolerate Knuckleduster's aggressive and violent attitude, especially when it gets out of hand. Despite that, the two are capable of working together during Vigilante missions.

Kuin Hachisuka
Unbeknownst to his fellow vigilantes, Kuin appears to be Knuckleduster's long-lost daughter. He is deeply dedicated to tracking her down, but it is unknown if she recognizes him or even wants to see her father again. Knuckleduster is aware that she is involved in the spread of the Trigger drug.

Giran
Knuckleduster appears to have a purely business relationship with the broker, obtaining equipment that's sometimes less than legal to deal with difficult Quirks.

Vigilante - My Hero Academia: Illegals

 * Knuckleduster vs Stendhal: Win

Trivia

 * His personality also bears a resemblance to Batman, a hero in American comics who is also extremely skilled at hand-to-hand combat that has no real powers.
 * He is also very similar the Wildcat a.k.a Ted Grant, a hero who is known for his aggressive fighting style and personality.
 * In Marvel Comics, he could be considered a hero close to Daredevil or Wolverine.
 * Knuckleduster's favorite things are cigarettes and beer.