Reiko Yanagi/Synopsis

U.A. Sports Festival Arc
Reiko finishes the Obstacle Race at 26th place. It is later revealed by Neito that she was a part of the group of Class 1-B students who went along with his plan to hold back in the Obstacle Race so that they could observe Class 1-A's Quirks and tendencies.

She teams up with Itsuka Kendo, Kinoko Komori, and Setsuna Tokage for the Cavalry Battle. Team Kendo attempts to snatch Team Midoriya's headband like many other competitors but Team Todoroki ends up freezing multiple rival teams, including hers. Shoto Todoroki proceeds to snatch Itsuka and Hiryu's headbands. When the event ends, Reiko and her teammates don't object once Itsuka suggests for their team to allow Team Tetsutetsu to participate in the 1 vs. 1 battles in their place.

Forest Training Camp Arc
Reiko is seen with Yui Kodai, Kinoko, Pony Tsunotori, and Setsuna when Classes A and B are heading out for the school trip. On the second day of the training camp, she listens along with the rest of her class as their homeroom teacher explains that they will be training their Quirks to improve them. When Class 1-B witness Class 1-A's intense training, the Wild, Wild Pussycats appear to explain that they will be there to help and guide them in their training. During the following days, Reiko trains under the Wild, Wild Pussycats' supervision.

On the night of the third day, Class 1-B acts as the scaring group during the test of courage exercise. However, that night the Vanguard Action Squad also attacks. Reiko is one of the eleven students who weren't knocked out by Mustard's gas but received injuries to varying degrees, being rescued later by Shota during the aftermath of the Vanguard Action Squad Invasion.

Shie Hassaikai Arc
Neito Monoma reveals that all of Class 1-B has passed the Provisional Hero License Exam.

Along with her classmate Itsuka Kendo, Reiko is one of the few class 1-B students who end up doing the Work-Studies.

U.A. School Festival Arc
Like the rest of her classmates, Reiko participates in the School Festival by helping her friend Itsuka prepare for U.A.'s Beauty Pageant contest. When Neito Monoma, Tetsutetsu Tetsutetsu, and Yosetsu Awase barge in to check on Itsuka, Reiko tells them not to barge in so unexpectedly. Later on, Reiko presumably watches Itsuka perform in the Beauty Pageant during the School Festival.

Joint Training Arc
Reiko, along with the rest of Class 1-B are pitted against Class 1-A as part of the Joint Training Battle. She is placed in the fifth round of match-ups. She is placed in the fifth round of match-ups after drawing lots, teaming up with Yui Kodai, Nirengeki Shoda, and Neito Monoma against Izuku Midoriya, Ochaco Uraraka, Mina Ashido, and Minoru Mineta. Hitoshi Shinso from Class 1-C is later put on her team.

As the matches go on, Reiko and her teammates watch Neito in exasperation as he shows further signs of insanity. While waiting for their upcoming match, they discuss the strategy to use against Izuku's team. Reiko notes that Izuku Midoriya could serve as a major threat to Team 5-B's victory, highlighting his newly-developed fighting technique. She then notes that Izuku could easily catch her team off-guard even by a second. Class 1-B decides that Izuku is their top priority, with Hitoshi and Neito combining their powers to defeat him while the other Nirengeki, Reiko and Yui face Izuku's teammates. Before starting the fight, let Neito copy her Quirk.

The fifth round of the Joint Training Battle commences, and Class 1-B proceeds to initiate their plan. As Ochaco Uraraka and Minoru Mineta attempt to catch their enemies off-guard, Reiko, Yui, and Nirengeki use this opportunity to attack them with a combined attack. Reiko begins the attack by sending multiple metal objects towards Class 1-A with her Poltergeist Quirk, that are enlarged by Yui and her Size Quirk, and Nirengeki uses his Twin Impact Quirk to add a second wave to the barrage.

As Mina defends her team with her "Acid Veil" Ultimate Move, Minoru notes that Reiko is aiming the objects at random targets as they don't seem to be homing in on their team. Upon scattering 1-A, Team 1-B vows to track down the remaining members in hopes of capturing them for a chance at victory.

However, 1-B's plan is interrupted when Deku's One For All Quirk begins to unleash black tendrils that send him flying across the battlefield. Reiko and her teammates notice Izuku destroying multiple sections of the battlefield. After Hitoshi and Ochaco manage to stop Izuku's out-of-control Quirk, Neito tries to ambush the two 1-A combatants. Neito's attempt fails, which leads to Reiko saving him from getting beaten down by Ochaco. The rest of her teammates follow up, allowing Mina and Minoru to navigate their location. With all participants together, the final match becomes an all-out brawl between 1-A and 1-B.

Class 1-B begins to gain momentum, but the tables are turned quickly. Izuku captures Hitoshi, and Ochaco manages to lock up Neito and returns to help her teammates. She karate chops Reiko, knocking her out, and pushes Yui into a trap made of Minoru's Pop Off balls, while, while Mina uppercuts Nirengeki, ending the battle and therefore the Joint Training Exercise with victory for class 1-A.

Despite the fierce competition and the result, the exercise ends on good terms between both classes, and later Class 1-B visits Class 1-A's dormitories for socializing and dinner.

Endeavor Agency Arc
Due to the increase of the villain activity, The Public Safety Commission demands all the student heroes for all academies to undergo practical field training, restarting the Hero Work-Studies program. With the announcement of Work-Studies program returning, Reiko and Itsuka return to the agency they went to the previous time.

Paranormal Liberation War Arc
The months go by until it's late March. Thanks to the police investigation and its spy Hawks, the Hero Public Safety Commission has found out the plans of the Paranormal Liberation Front and its allies. With this information, the Commission organized a large force of Pro Heroes, divided into several teams to take down the villain organization.

While a team of heroes raids the Jaku General Hospital, where the Nomu are created, another team does the same at Gunga Mountain Villa, the Front's main headquarters. Reiko is a member of the Villa Backup Team along with some of her classmates and Class 1-A students. Their mission is to provide support to the heroes who raid the Gunga Mountain Villa and prevent villains from escaping.

Although at first the heroes had the upper hand, the situation goes south when Tomura orders Gigantomachia to come to him, bringing the League members with him. This results in the giant defeating many heroes as he simply walked towards Jaku City.

Kyoka detects how the gigantic brute is approaching, and warns her teammates in fright, then Momo receives a call from Midnight. She tried to stop Gigantomachia but failed and ended up severely injured, so she informs Momo that to stop him they must put Gigantomachia to sleep with an anesthetic, before losing contact.

Under the instructions of Midnight, Momo started conducting a plan to stop the villains. Momo creates vials filled with sedative and gives one to each teammate, so if one of them chucks it into Gigantomachia's mouth, he should fall asleep, and with the help of Juzo and Minoru, create a large trap for Gigantomachia. As they set up the trap, they are informed that several commanders of the PLF are riding on Gigantomachia's back.

As they planned, Gigantomachia steps into the trap and falls to the ground, and the students begin their assault. While some try to make him swallow a vial, Reiko helps other team members to attack the commanders. Using her Poltergeist Quirk, Reiko lifts Denki up high enough for himto attack the villains, but before he can do it, he gets hit with debris released from marbles shot by Mr. Compress with his prosthetic.

The League of Villains and Gigantomachia manage to repel the assault, and Dabi creates a fire barrier to prevent the students from getting close. The students outside the wall of flames try to contact the others, while Reiko has Denki resting on her lap, asking if he is okay and apologizing for messing up earlier. Denki weakly responds by saying the lap pillow is nice.

Despite being repelled, the students continue the assault, which now has the support of several heroes who had come to help them. Not without great difficulty, Eijiro gets Gigantomachia to swallow a vial with sedative. More heroes led by Majestic arrive to take charge of Gigantomachia now that he has ingested the sedative, because the more he moves the faster it will spread.

Final War Arc
With the heroes' numbers dwindling rapidly, the remaining heroes prepare themselves for the Final War against the army of villains led by All For One. While most of the Heroes successfully draw out the villains and split them up all over Japan, Reiko and several other members of Class 1-A and 1-B are assigned to the Jaku Hospital Ruins, in order to protect Gigantomachia's containment facility, after he fell during the War.

Sure enough, a section of the Paranormal Liberation Front appear and attempt to free the beast, leading to a big battle. During the fight, they heard the news that Shoto Todoroki has defeated his oldest brother, Dabi, and that gives the heroes the push to keep on fighting.

Reiko and the Heroes defend the Jaku Hospital with their lives; however, the battle for the Jaku Hospital is falling to the villains when PLF commander who killed Midnight flies in the air along with several other soldiers, making Juzo Honenuki’s Quirk ineffective against airborne villains who can fly above his soft ground. The commander has been given a device by All For One which sends a high frequency recording sound transmitter to signal Gigantomachia inside of the containment facility, broadcasting All For One’s voice through the walls since Machia’s Dog Quirk allows him to have sensitive hearing.

Fearing the worst-case scenario since the Paranormal Liberation War, Mt. Lady tries to smack the floating villains with a giantified wrench resized by Yui Kodai before Machia suddenly broke through the highly fortified containment and knocked her down. Reiko and the rest of the students watched in horror as Machia breaks free from his containment, and Eijiro finds the Sludge Villain suffocating Hitoshi Shinso to death.

However, Mina pushes her Quirk to its maximum viscosity and blasts out her new Ultimate Move: Acidman – Alma at Machia’s claws. The acidity was so potent that it melted right through Machia’s hardened skin. Mina then comes over to aid Eijiro to free Hitoshi from the Sludge Villain by shoving her hand into its sludge mass body and pour acid inside. The Sludge villain’s body is becoming a liability as the acid is mixing with the sludge and was forced to spit out Hitoshi before trying to escape, but the villain starts losing his mass. Hitoshi uses his Persona Chords on Machia, allowing him to brainwash the behemoth and orders him to attack the airborne villains, annihilating every single one of them.

With Hitoshi now in full control of Machia, Naomasa calls for backup at the Guna Mountain and so, Reiko and the rest of the containment team rides on Machia toward the Gunga Mountain Villa where all of the remaining heroes are engaging All For One.