Mei Hatsume is a young woman with pink locks and yellow eyes with cross-hairs for pupils. She is usually seem wearing protective goggles, fingerless gloves as well as many other her other gadgets on her person.
Mei is a smart, off-setting, and assertive girl, often making those around her uncomfortable. She loves creating gadgets, which she refers to as her "super cute babies". Mei has a habit of "going straight to the point", and is very shameless and opportunistic when it comes to advertising her inventions. While talking to people, she has a habit off getting awkwardly close to them, almost jumping into their faces, which usually causes them to back away from her.
Mei shows no fear when it comes to failing, seeing it as an opportunity to learn and do better next time, which is why she doesn't mind when her inventions fail. Mei can be seen as self-centered due to putting her love of inventions and gadgets above others, but this selfishness is not negative but rather out of motivation to improve herself.
Mei Hatsume takes to the field with her classmates from the Department of Support. After the opening ceremony, Mei competes in the Obstacle Race.
When Ochaco Uraraka and Mina Ashido reach The Fall section of the course, Mei makes herself and all of her gadgets known. Mina questions why it is Mei is allowed to wear special gear, to which Mei replies she developed them herself and it allows for a more fair competition in the Festival because Hero Course students receive training. Mei uses her Wire Arrows and Hover Soles to cross tightrope-laced abyss with ease, laughing gleefully as she does it. She eventually finishes the race and places forty-first, qualifying her to compete in the Cavalry Battle.
While choosing teams for the Cavalry Battle, Mei spots Izuku Midoriya, the first place contestant, and confronts him. She pitches to join his team because all eyes are on him and if she joins him, then all eyes will be on her and her "babies" as well. Izuku is startled by Mei's assertive personality, but he is won over after she shows off several of her gadgets. Izuku even recognizes one from the Pro-Hero Air Jet, and the two have a friendly discussion about it.
Once the Cavalry Battle begins, Izuku is forced to use the Jet Pack to escape pursuing teams. Mei asks how her gadgets perform, and is joyous to hear when Izuku replies her "babies" are amazing. After getting trapped by one of Minoru Mineta's spheres, Izuku is forced to break one of the hover soles, much to Mei's dismay. After finally getting away, Mei and her team are confronted by Team Todoroki.
Denki Kaminari attacks using his electricity, which short circuits Team Midoriya's jet pack. When it fails to work and Team Midoriya are unable to flee from Team Todoroki, Mei comments that her baby needs some upgrades. Thanks to Izuku's strategy, Team Midoriya are able to evade Team Todoroki for the back half of the round. However, their luck runs out when Tenyas Iida uses his special Recipro Burst technique to steal Mei's team's points in an instant. Mei agrees with Fumikage Tokoyami that they should try for other points, but Izuku refuses and they engage Team Todoroki again. 
Izuku is able to steal one of their headbands, but Mei notices it is the wrong one. They try one more time to recover their points, but run out of time as the Cavalry Battle ends. When Izuku tries to apologize for losing, Mei and Ochaco point him towards Fumikage, who reveals he was able to steal a headband worth enough points to advance. Team Midoriya takes fourth place, and Mei qualifies for the finals. 
After a short break following the completion of the second round event, it is announced the sixteen qualifiying students will duel in a one on one fighting tournament. Once the matchups are announced, she approaches "legs" to ask him if he's Tenya Iida, to which he confirms.
Mei offers Tenya some of her equipment and tells him it's to keep the fight fair between them. Moved by her sportsmanship, Tenya agrees. However, when their fight begins Mei manipulates Tenya into showing off her gear while evading his pursut. She uses her Quirk to keep an eye on the support company representatives as she transforms the battle into a commercial for her support items.
For the next ten minutes, Mei continues her fight while explaining the features of her items to the audience using a mic attached to her headgear. Satisfied with her exposure, Mei steps out of bounds and eliminates herself from the tournament, allowing Tenya to advance to the next round. Mei thanks Tenya for allowing her to use him and apologizes for it, much to Tenya's annoyance.
Mei appears again as Izuku visits the workshop to improve his hero costume. An explosion catapults her through the door and lands on Izuku as he tries to enter. She recalls Izuku only to turn away and tell him that she's busy in the workshop. Upon hearing that Izuku wants to upgrade, she turns all her attention to him though. While Power Loader and Izuku discuss how they can upgrade his costume, Mei grabs onto Izuku to feel his muscles. Mei equips Izuku with her 49th invention, a Power Suit. However, the armor moves independent from Izuku and hurts him, causing her to apologize for programming the motion range wrongly. Upon hearing Tenya's request for a gadget that lets him cool his legs, Mei equips him with her 36th gadget, an armbrace that suppresses heat generation, which promptly sends Tenya into the ceiling. When Tenya complains, since his quirk is located in his legs, she reasoned that he could run with his arms, to cool his legs. Powerloader scolds her for her carelessness and she returns to her work. Shortly after she tries to improve Uraraka's costume with some gadgets, much to Uraraka's dismay.
In the end, Izuku settled for an armbrace that reduce the strain on his arm and boots with a coil-mechanism, that absorb some of the impact force of his kicks.
Quirk and Abilities
Expert Inventor: Mei is very smart and innovative, creating many different pieces of equipment on her own that can help her in many situations. She relies mostly on her inventions to traverse obstacles and tasks. Power Loader acknowledges Mei's talent in the field of inventing, calling her one of a kind.
Overall Abilities: Outside of her intellect, Mei mostly acts as a support rather than facing battles directly. However, she proves to be a capable combatant as seen in her match against Iida, where it lasted for ten minutes with Iida unable to do anything to her despite his speed advantage and only winning when she forfeited.
Hydraulic Attachment Bar (油圧式アタッチメントバー Yuatsu-shiki Atatchimento Bā?): Created by Mei.
Power Suit: A mechanical suit that senses muscle contraction and aids in movement. Mei's 49th invention.
Electric Booster: A speed booster that generates minimum heat. Mei's 36th invention.
Mei and Izuku first met during the U.A. Sports Festival. Mei took an interest in Izuku when he got first place in the Obstacle course and as a result, got the ten million point headband. She saw this as an opportunity to bring attention to her inventions by using Izuku and approached him before the Human Calvary Battle. In return for joining his team, she offered him and the other teammates support equipment to aid for their battle.
After the U.A. Tournament, the two would not meet again until Izuku wanted Power Loader's help in improving and redesigning his costume. Mei recognized him during their second encounter, but does not remember his name and dismissed it in order to go back to her inventions only to return her attention back to him when he brought up his purpose for entering the workshop. She provided Izuku some options for improvements on his costume and created Izuku's Costume Gamma.
Overall, the two generally get along well. Izuku has no problem talking with Mei during their first encounter. They got acquainted over a jetpack Mei created that was similar to a hero Izuku was familiar with.
The two met again and Mei recognized Izuku but forgot his name though she remained kind to him even more so after he complimented one of her inventions. Izuku also appears to tolerate Mei more than some of his classmates like Iida and Ochaco since he shares some similarities to her as he creates ways to counter the quirks of others and rambles as she does about gadgets.
Mei frequently invents a lot of inventions at U.A., even during her break. As a result, she spends a lot of time in Power Loader's workshop and in his company. Power Loader tolerates Mei's presence and values her importance to the students. However, when her behavior gets out of hand, he tries to keep her in line much to Mei's dismay. Despite that, the two are friendly with one another, with the occasional petty arguments that happen because of Mei.
Ochaco has a somewhat rocky relationship with Mei, due to her direct nature. During her interactions with Mei, she Izuku was always present as well and Mei often went awfully close to Izuku, much to Ochaco's dismay. She was slightly jealous when Izuku praised Mei's "super cute babies". During their second encounter, Mei landed right on top of Izuku and shortly after, Mei felt Izuku's body and noted that it's surprisingly muscular. All of that made Ochaco visibly uncomfortable but she managed to remain polite and civil.
Mei approached Iida before their match with Mei offering Iida support equipment. Iida naively accepted her supposed generous offer, only to realize too late that she was using him to promote her inventions. Despite her apology, Iida dislikes Mei for taking advantage of his noble nature. This dislike still remained with Iida as seen in their second encounter. His dislike for her escalated when she forgot and dismissed his name, and also made him unwillingly use one of her inventions that he rejected. He openly voiced his dislike of her to Power Loader.
- Her name comes "invention" (発明 hatsumei?) and "eyes" (目 me?), but the second and third kanji have switched positions.
- Mei was originally going to be a male.
- In the First Popularity Poll, Mei ranked 20th, which ties her with Toru Hagakure.
- Mei's favorite food is chocolate.
- Mei likes steampunk style, as evidenced by her usual gadgetry.
- Mei ranked in the Top 16 of the U.A. Sports Festival First-Year Stage.
- (To Power Loader) "Heh heh heh... Failure is the mother of invention, Power Loader sensei. Thomas Edison once said that. Just cuz a creation doesn't work as intended doesn't mean the effort is wasted..."
- (To Tenya Iida about using his arms instead of his legs) "If you want to cool your legs, all you have to do is just run with your arms!"