Mei Hatsume/Synopsis

U.A. Sports Festival Arc
Mei 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 Mei is allowed to wear special gear, to which Mei replies she developed them herself and it allows for a more fair competition at the Festival because Hero Course students receive training. Mei uses her Wire Arrow 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 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 jetpack. 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 Iida some of her equipment and tells him it is 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 pursuit. 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.

Final Exams Arc
Mei is mentioned by All Might; according to All Might, Mei's High-Density Weights won a competition, so they were used as the handicaps for the teachers to wear in the exams.

Provisional Hero License Exam Arc
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. However, upon hearing that Izuku wants to upgrade, she turns all her attention to him. 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 range of motion incorrectly.

Upon hearing Tenya's request for a gadget that lets him cool his legs, Mei equips him with her 36th gadget, an arm brace with rocket motors, 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. It is this suggestion that leads Izuku to develop his new set of moves, Shoot Style, which utilize his legs more than his arms. Power Loader scolds Mei for her carelessness and she returns to her work, though he remarks that Mei is an outstanding student with a remarkable ability to invent. Shortly after, Mei tries to improve Ochaco's costume with some gadgets, much to Ochaco's dismay. In the end, Izuku settled for an arm brace that reduces the strain on his arm and boots with a coil-mechanism, that absorb some of the impact force of his kicks.

U.A. School Festival Arc
Mei was out following one of her gadgets and comes across Izuku and All Might who caught her device. All Might (while disguising his voice) hands her invention back to her, as she states it was just acting up. Mei then notices Izuku and tells him the item that he requested is similar to one of her inventions and is customizing it for his use, to which he thanks her. Mei leaves while following her device.

Later on, she finds Izuku training and tells him his new gloves are complete and gives them to him. She hands him the instruction manual for them before running off.