Tatsumaki/Synopsis

History
Tatsumaki was seemingly held caged up in a certain facility by people in lab coats.

Experimentation
Her psychic abilities eventually led to her being taken away from her adopted family at the age of seven by scientists interested in studying her powers. Her parents were given money for complying. She was tested on by the scientists because of her extraordinary powers. They rewarded her with candy and toys for cooperation, but was denied to go outside. Moreover, she was kept locked up in a cell whenever she wouldn't use her powers. 18 Years ago, when she was 10, a monster outbreak occurred while she was still locked in a cell, leaving her alone to fend off the monster. Luckily, Blast managed to come to Tatsumaki's rescue.

Rumored Monster Arc
Tatsumaki visited the Z-City branch of the Hero Association to see if she can investigate the restricted area of Z-City. However she is informed by the Bearded Worker she didn't need to do, since the Association thought that an S-Class wasn't necessary for the job. She leaves only to call the worker an idiot. Later after both Golden Ball and Spring Mustachio return badly injured, Tatsumaki is enraged and yelling at the worker saying she should have gone. The worker shows her a picture of the destruction, saying even she might have had a hard time. Tatsumaki tells him she could handle it then calls him an idiot again.

Alien Conquerors Arc
Tatsumaki is sent to the mountains by plane to defeat the Ancient King, only to be called back to the Heroes Association Headquarters by cellphone, which angers her greatly. She quickly ends the fight by sending a meteor crashing down on the Ancient King.

Tatsumaki later met Saitama at the Hero Association HQ as Bang invited him to the Hero Association S-Class Meeting. She becomes indignant at his presence, asking who let Saitama in, pointing out that he is a lower-ranked hero, and accusing him of only coming to the meeting to see the S-Class heroes up close. A perplexed Saitama mistakes her for a child and asks if she is lost, prompting Genos to explain her identity. Genos observes that most of the S-Class Heroes have arrived and goes to take his seat, causing Saitama to ignore her much to her chagrin. Upon the meeting's inception, Bang asks what the heroes were called to the meeting for. Tatsumaki states that she had to wait for two hours without hearing an explanation. During the alien invasion of A-City, Tatsumaki prepares to set out to engage with the enemy and their aircraft. Because of King's moniker of "The Strongest Man on Earth", fellow S-Class hero Superalloy Darkshine ask for King's opinion on how to deal with the spaceship, to which his answer is deemed pathetic by Tatsumaki. Frustrated by King's inability to take the initiative, she decided to take down the UFO alone and rudely declining Genos' offer to assist.

At the site of the Heroes' engagement with Melzargard, the aircraft of the Dark Matter Thieves fired their cannons towards the ground in an attempt to eliminate Bang, Atomic Samurai, Metal Bat and Puri-Puri Prisoner, only to be intercepted by Tatsumaki and was redirected towards the aircraft. In the midst of the battle, Tanktop Master attempted to help her by throwing concrete blocks at the enemy, until he realized that Tatsumaki's psychic ability can do more than Tanktop Master could ever accomplish on his own. The spaceship eventually fell, though she was not convinced it is because of her doing. After the fight is over, Saitama busted out from the wreckage, and is asked by Tatsumaki if he came on his own. Instead, the latter ignores her and started a conversation with Genos. Angered by being ignored, she started insulting Saitama and pinned Genos to a wall after he addresses her as a kid. Bang stops her when she is about to attack Saitama, telling her to act properly as an S-Class hero.

The Blizzard Group Arc
Tatsumaki makes a brief appearance in Fubuki's vision.

Monster Raid Arc
Tatsumaki causes an explosion in the city where Do-S and Fubuki are fighting. When she arrives, she immediately tells Fubuki to go home and that she will handle the rest. Do-S orders her love slaves to attack Tatsumaki as a distraction as she escapes. Tatsumaki immobilizes all of the love slaves and tells Fubuki that they will only get in her way and to not call them her allies. She then takes off to find the rest of the monsters.

Super Fight Arc
She later appears arriving in I-City, killing a wounded Hundred-Eyes Octopus, much to the chagrin of Flashy Flash. She berates the heroes and then leaves as Flashy Flash tries to berate her.

Tatsumaki is one of heroes seen fighting against monsters, when Suiryu is calling for help.

Monster Association Arc
She is shown to be summoned by the Hero Association to attend meeting to prepare for the operation of attacking the Monster Association. With her usual superiority complex, she brags that the Monster Association is just a bunch of cowards and if they were not, they wouldn't prove a match against her.

When she is briefed about the situation by Sekingar, she suggests reducing Z-city to rubble to kill all the Monsters while disregarding the life of the hostage.

The S-Class heroes, Tatsumaki, Child Emperor, Kamikaze, Pig God, Flashy Flash, Superalloy Darkshine, Zombieman, Puri-Puri Prisoner and Sekingar attend a meeting and they reassure Narinki that they will rescue his son. They each receive a transmitter that will show their location to each other. She gets into an argument with Sweet Mask who wants to lead the strike force. Ultimately, the situation is calmed by King who just arrived.

The Monster Association strike team head out to Z-City to confront the Monster Association. At the ghost town within Z-City, the battle begins as Tatsumaki battles Evil Eye. She kills the monster.

She heads into the Monster Association HQ at her assigned route. Later she is seen challenging Gyoro Gyoro. She manages to annihilate Gyoro Gyoro in their fight. She puts up a barrier to protect herself from Orochi's electricity.

When she hears Orochi was killed by a bald dude, she thought it was Darkshine. At the end of her fight with Gyoro Gyoro she tears a meat puppet out of its body and realizes that Gyoro Gyoro is really Fubuki's friend turned turned enemy, Psykos.

Monster Association Arc
After storming the headquarters of the Monster Association with several other heroes, Tatsumaki confronts the leader and rips the entire base out of the ground. She then battles against the remaining Dragon level monsters, but is attacked from behind by the aforementioned leader Psykos, and is weakened.

Being viciously battered and beaten around, her clobbering is momentarily postponed by the arrival of her sister Fubuki and some of the other heroes who attended. As they are steadily being whittled down by the enemies relentless assault, Tatsumaki re-enters the fray boasting that the other heroes are useless without her. She focuses her telekinesis on taking down Evil Natural Water by dispersing his liquid form with sheer pressure.

Soon afterwards, she is attacked by Black Sperm but quickly dispatches all of his combination attack forms. In the short instant she sweeps aside his assault, Black Sperm takes Busaiku hostage as he prepares his final trump card by fusing ten trillion cells into Golden Sperm. Golden Sperm proves so powerful he easily blows through the weakened Tatsumaki in an instant. She isn't down for long however, she soon regains consciousness and attempts to snap Golden Sperm's neck but the creature's will is too powerful and rebukes her telekinesis.

After, Garou dispatches both Sperm entities when he reaches his second transformed state. Tatsumaki attacks him by flinging a giant bolder at the latter, but he easily deflects it by smashing the rock to dust with one blow, commenting on how her telekinesis wasn't much as her sister, Fubuki, was. When told by the human monster what he'd done to her, she flew into a rage, hurling whatever she could find his way.

Garou, now declaring himself a Disaster Level God; going so far as naming his new form of martial art: Monster Calamity God Slayer Fist. He would go on to decimate the remaining heroes while fending off Tatsumaki's rock barrage with ease. Tatsumaki focuses the last bits of her psychokinesis to pin him in place while the other heroes attacks him. Garou quickly adapted to her telekinesis, soon releasing himself from her mental bind. She defiantly states that if she were in top form she'd wipe the floor with him in five seconds. As soon as Garou moves to finish her, Tatsumaki passes out from her injuries and the strain her powers imposed on them.

Psychic Sisters Arc
She attempts to kill Psykos and severely injure the Blizzard Group who were blocking her. Tatsumaki is eventually confronted by Saitama. Saitama takes her out of the building to avoid more damage. She gets angered at Saitama and proceeds to attack him. Speed-o'-Sound Sonic gets involved, still hunting Saitama and promising to defeat him. He is quickly taken out. Her wounds from the Monster Association battle open up, so she stops fighting. Like in the case of Garou, she said that if she was at top strength, she could flatten Saitama in 5 seconds. He asks her why is she a hero and why she keeps others away, only for her to reply "Because.. Bla-" but then decides it's not worth it to respond. She reminiscences about the time where she was saved by Blast 18 years ago when she was young after a monster had escaped. She then asks herself, "When will you be back, Blast?"