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 denied her requests to go outside. Moreover, the scientists locked her 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. He then introduced himself to the young esper and questioned her on why she didn't use her psychic powers to save herself. Tatsumaki answered that her powers weren't working, but Blast recognized that she was lying, and warned her to not expect anyone to save her next time. An unknown number of years before the events of the main story, Tatsumaki saved Fubuki from bullies at their school, launching a kid who tried jumping on her into the air. The rest of the kids ran into the school building, but Tatsumaki retaliated by momentarily lifting the entire building into the air. She then told Fubuki to either come to her or retaliate when she was being bullied.

Rumored Monster Arc
Tatsumaki visits 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 come, since the Association thought that an S-Class wasn't necessary for the job. She leaves, calling the worker an idiot. Later, after both Golden Ball and Spring Mustachio return badly injured, Tatsumaki is enraged and yells 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 fight 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 meets Saitama at the Hero Association HQ due to Bang inviting 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, to which 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 asks for King's opinion on how to deal with the spaceship, but King states that they can't do anything due to the ship being too far away. Tatsumaki deems this answer pathetic and decides to take down the UFO alone, rudely declining Genos's offer to assist.

At the site of the Heroes' engagement with Melzargard, the aircraft of the Dark Matter Thieves fires cannons towards the ground in an attempt to eliminate Bang, Atomic Samurai, Metal Bat and Puri-Puri Prisoner, only to be intercepted by Tatsumaki, who redirects them back at the aircraft. In the midst of the battle, Tanktop Master attempts 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 falls, though she is not convinced it is because of her doing. After the fight is over, Saitama bursts out from the wreckage, and is asked by Tatsumaki if he came on his own. He ignores her and starts a conversation with Genos. Angered by being ignored, she starts insulting Saitama and slams Genos against a wall after he addresses her as a brat in retaliation. 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 argue with 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 on who wants to lead the strike force. Ultimately, the situation is calmed by King who arrives from Z-City.

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 fights Evil Eye. She kills the monster, twisting it into oblivion.

She heads into the Monster Association HQ at her assigned route. Later she is seen challenging Gyoro Gyoro. She manages to quickly gain the upper hand over 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 wonders if it was Darkshine. At the end of her fight with Gyoro Gyoro she tears a humanoid figure out of its body and realizes that Gyoro Gyoro is really Fubuki's friend turned enemy, Psykos.

Tatsumaki quickly realizes that the humanoid is nothing more than another meat puppet, and that Psykos's actual body is located deep underground. She quickly locates Psykos and pulls her up in spite of the latter's attempted resistance. After momentarily questioning Psykos on Tareo's whereabouts, the two clash, and Tatsumaki easily restrains Psykos and interrogates her for intelligence. After receiving the requisite intel, Tatsumaki briefly argues with Sweet Mask via transmitter regarding the fate of Narinki's Private Squad, but is cut off by Orochi, who reappears and attacks. As Tatsumaki fights Orochi, she wonders if he's a cadre and expresses frustration at the inability of the other heroes to rescue Tareo, stating it would be easier if she could just destroy the base. When Orochi's form is taken over by Psykos, Tatsumaki continues fighting, but quickly realizes that Psykos's psychic power has increased substantially. She sustains moderate injuries in her struggle to hold Psykos off, but receives word from King of Tareo's safety. Tatsumaki declares that she no longer needs to hold back and begins to unleash her full power.

Using the location of the transponders, Tatsumaki encloses the underground heroes in psychic barriers and lifts them up to the surface, with the exceptions of Zombieman, Flashy Flash, and Saitama, who do not have transponders on them. After ensuring their safety, she pulls the Monster Association base aboveground, flying out of a building moments before Psykos emerges. Tatsumaki notices that Psykos is absorbing energy from the tendrils on her lower body. She attempts to drill through her now that they're outside, but is shocked when Psykos unleashes a beam of incredible destructive power, momentarily cutting off a sliver of the planet. Tatsumaki wonders where Psykos's power is coming from, and when told of Psykos's plan to absorb every life form, deems it stupid and mocks her. When Psykos attacks, Tatsumaki flies between the energy beams of her dragons, staying high above the surface as to keep the line of fire away from the ground. She notices King leading Tareo away from the battle and mentally praises him for leaving the battle to her. She then lifts several large rocks out of the ocean and hurls them at Psykos, attempting to trap her. Psykos breaks out, and a whirlwind of rocks and energy fills the sky as the two unleash their power. However, Tatsumaki then decides to create a dummy using rocks and imbue it with her esper power to distract Psykos amidst the rocks flying everywhere. While Psykos attacks the dummy, Tatsumaki flies to the bottom of the uprooted Monster Association base and enters one of the tendrils of Psykos and Orochi's root system, muting her psychic signature as to not be detected. She then flies up to Psykos's main body, commenting on how it's hollow from the inside, and quickly destroys it by twisting it. She then decides it's time to pull out the infiltration squad, extricating Atomic Samurai and Puri-Puri Prisoner from the building.

However, before she can finish the job, both her hands are impaled by the blades of Psykos's quickly-reforming body, and she is hit with a powerful jolt of psychic power. Psykos charges up another powerful energy beam, but Tatsumaki is saved by Genos, who launches an energy beam of his own to intercept. As Genos takes on Psykos, Tatsumaki angrily tells him to get out of the way, stating that King left her this responsibility. Genos responds that King only left her the job until Saitama's arrival, adding that it's the disciple's duty to help with the teacher's work. He then tells her to attack Psykos's body while he handles her energy beams, and the two heroes face off against the monster.

Original Webcomic
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 boulder 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 attack him. Garou quickly adapts 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 of her powers.

Psychic Sisters Arc
Tatsumaki shows up at the building where several other monsters are being held with the intent to kill Psykos. The Blizzard Group attempts to hold her back with psychic binding, but she easily incapacitates them. She bursts into Psykos's holding cell and asks why the former Monster Association head is still alive. Fubuki attempts hold her back, telling Saitama to take Psykos and run. However, Tatsumaki easily breaks out of the bind and chides Fubuki for letting her heart grow weak, stating that the two of them don't need anyone else and calling the Blizzard Group weak. Fubuki gets angry at this and attacks Tatsumaki with her Hell Cluster. Tatsumaki is unharmed by the onslaught of rocks and proceeds to tell Fubuki that she'll have her younger sister retire from hero work and take care of everything for her from now on. She restrains Fubuki with her psychic power, but Fubuki uses Psychic Whirlwind to break out and momentarily block Tatsumaki's psychokinesis. Fubuki then unleashes Hell Storm, but this attack again proves ineffective, failing to harm Tatsumaki. However, Tatsumaki recognizes Fubuki's improvement and praises her for her strength, momentarily surprising the younger esper. However, Tatsumaki goes on to say Fubuki doesn't need friends and that she'll cut off the Blizzard Group for her younger sister. Before she can go any further, she is stopped by Saitama, who jumps out of the building with her to avoid more damage. She gets angry 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?"

Neo Heroes Showcase Arc
Tatsumaki is later dispatched to P-City to take on the Dragon-level mysterious being Aggregation. She expresses disgust and shock as the mass of insects splits and begins to attack.