Costume

A costume (コスチューム) is a distinguishing outfit worn by a hero or villain.

Heroes
Pro Heroes and Hero Course students alike often don specific battle wear to fight and strengthen their Quirks. Hero costumes are often equipped gear to help Pro Heroes do their jobs most effectively, reducing risk to themselves while increasing their efficiency.

Costumes are generally tailored specifically to the hero in order to amplify their abilities and weaken their drawbacks. They also help the public recognize them and distinguish themselves from other heroes. Their designs can vary on a wide scale, including simple costumes, bodysuits, skinsuits, spacesuits, sets of armor and various other outfits depending on the Quirk functions and style preferences of the wearer. Support companies and genius scientists are the masterminds behind creating costumes for heroes.

For student heroes at U.A. High School, the costumes are developed at the school's expense. Costumes receive alterations throughout a student's career as they learn more about themselves and their Quirks. Minor alterations and support items are added by Power Loader in U.A.'s Development Studio, whereas bigger modifications require formal applications and are outsourced to a support company.

Mirio Togata's costume was designed to help him use his Quirk without losing his clothes. His costume is lined with fibers created from his hair. This is just one specific way costumes help student heroes deal with their weaknesses.

Costumes can also include battle prosthetics that are meant to help heroes with physical disabilities. The most prominent example of this is Ectoplasm, who wears replacement legs that are designed for combat.

Villains
While heroes are welcome to proudly don their costumes, villains do not have access to support items via legal channels. Villains generally use costumes as a way to hide their identity rather than distinguish themselves like Pro Heroes. There are exceptions though, Spinner wears his costume as a homage to his idol, the Hero Killer: Stain, meaning that villains can wear costumes that represent a message they wish to spread.

Support items and villain costumes are sold through the black market using brokers like Giran. He provided the Vanguard Action Squad with the proper gear to help support their Quirks. Himiko Toga received the most dramatic change in costume; her equipment functions to help her gather blood for her Transform Quirk.

Like with heroes, villain channels can also deal in prosthetic limbs; Mr. Compress was given a prosthetic arm by Detnerat that allows him to shoot his marbles through his fingers. Another example is Re-Destro, who was fit with mechanical legs, although they don't support his Stress Quirk that well.

Known Costume Developers

 * Mei Hatsume: U.A.'s Support Department student. An energetic inventor who has come up with countless ideas for hero support items.
 * Power Loader: U.A.'s teacher and head of U.A.'s Development Studio. Responsible for overseeing and developing minor alterations in costumes for U.A.'s hero students.
 * David Shield: One of the most well-known costume designers in the world. He designed all four of All Might's costumes during his run as the No. 1 Hero. It’s the support of these costumes that allows All Might to fight at full power without risking damage to himself or his clothing.
 * Detnerat: A company that specializes in developing clothing and support items for civilians with abnormal body's or anatomy. Recently entered the hero costume market. It has ties with the black market, providing villains with equipment that collects their battle data and self-destructs to avoid being traced back to them.

Trivia

 * Following the debut of the R-Rated Hero: Midnight, the government passed a law limiting the amount of skin that could be exposed on a hero costume, due to Midnight wearing an inappropriate costume.
 * Many in Class 1-A share costume designers:
 * Tsuyu Asui, Momo Yaoyorozu, Minoru Mineta, and Mina Ashido all share the same costume designer.
 * Ochaco Uraraka and Katsuki Bakugo share the same costume designer.
 * Kyoka Jiro and Denki Kaminari share the same costume designer.
 * Izuku Midoriya's later costumes share the same designer as Shoto Todoroki's.
 * Hanta Sero and Eijiro Kirishima share the same costume designer.
 * The following students currently have no listed connections between costume designers amongst each other: Yuga Aoyama, Toru Hagakure, Tenya, Rikido Sato, Mezo Shoji, Koji Koda, and Fumikage Tokoyami.