Flashy Flash/Synopsis

History
Flashy Flash was trained in the Ninja Village and participated in the 44th class along with Speed-o'-Sound Sonic. Upon graduation, he was the strongest member of his class, but caused an incident that left Sonic the only other survivor of their class and effectively ruined the village according to Gale Wind.

He left the village after some time. For some unknown reasons, he was hunted by multiple assassins and criminal masterminds but he managed to dispatch all of them during his spare time in his hero's activities. Some criminals and assassins Flashy Flash killed include Aburabozu, the king of organ traders, Harold the drug kingpin, heart collector Burigura, phantom thief Chimagusa, the invincible pirate captain Devil Storm and the higher ups of the Coalition of Assassins.

Alien Conquerors Arc
Flashy Flash appears at the S-Class Hero Association meeting. Although he was at the meeting, he remained quiet for the majority of the meeting. When the Dark Matter Thieves attacked, he left the scene along with other heroes.

Super Fight Arc
Flash appears in I-City where he assists the gathering heroes prepared to fight against Hundred-Eyes Octopus. He uses his powerful speed to rush toward the monster and stabs one of its eyes. After that, he proceed to slash all the eyes of the monster until it goes berserk. As Flashy Flash begins to unleash his special technique to finish the monster for good, Tatsumaki comes in time, lifts the monster up in the air and crushes it into a giant ball.

After the death of the monster, he and the others heroes are berated by her. However, he also proceeds to berate her back, but is stopped by the other heroes. The heroes end up parting ways for now.

Monster Association Arc
The S-class heroes, Flashy Flash, Tatsumaki, Child Emperor, Pig God, Kamikaze, 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.

The meeting continues as they plan out their attack on the Monster Association. Flashy Flash gets into a argument with Tatsumaki before Sweet Mask barges into the meeting. When Sweet Mask demanded to take leadership over the S-Class heroes, Flashy Flash taunts Sweet Mask to try and take control with force. Before the argument could escalate further, King arrives and settles the situation. Flashy Flash is suitably impressed with King overnight monster elimination at Z-City. When Sweet Mask backs down, Flashy Flash sighs. Flashy Flash leaves with various other heroes to attack the the Monster Association.

Flashy Flash arrives at the ghost town of Z-City with various other heroes. He compliments Shadow Ring on her ninjutsu and asks where she learned them. Shadow Ring replies not from the same place as Flashy Flash she skitters off. Flashy Flash mentions that it couldn't be his ninja village as his village doesn't train any woman. Flashy Flash kills various monsters from the initial monster attack. After dealing with the monsters on the surface, Flashy Flash heads underground into the Monster Association base alone. There he dispatches several monsters before being confronted by Hellfire Flame and Gale Wind.

The monsters compliment Flashy Flash on his speed before they do battle. During the fight, Flashy Flash destroys the corridor, and Gale Wind rotates one of the blocks they were standing on in order to battle in a more open area. As they fought, Gale Wind explains that they will eliminate all foes who are possibly a threat, and explains the purpose of going after Flashy Flash was because he viewed other ninjutsu masters as rather troubling. Flashy Flash sprints off at speeds neither monsters could track, and he then tells them to unleash their full power as monsters.

Eventually, they are both forced to reveal their monster forms after realizing they are outclassed in their human forms. Flashy Flash's eyes widen in surprise at their increased speeds, and is barely able to block both of their attacks. Round 2 of the battle between the three ninja then begins. They continuing battling, and the two monsters are able to pressure Flashy Flash, managing to make him cough up blood, but once the hero became serious, he strikes both of them with a series of kicks, and then slices both of them in half, ending their lives.

Flashy Flash leaves the battlefield and arrives at a junction. He goes to consult his Locator to see where he is but finds that he lost it in the battle.

Monster Association Arc
He meets up with Saitama, who he mistakes for an enemy. He was very surprised when Saitama was able to dodge and counter his extremely quick attacks. They finally get to where the fight with Garou was going on. Along with Darkshine, his true speed and abilities were shown. He left his mark as perhaps one of the fastest characters in the series, but was ultimately defeated. During their attack on Garou, Zombieman states that even the strength of Darkshine and speed of Flashy Flash would not be enough.

Fall of the Hero Association Arc
By the time the Hero Association was about to fall, Flash acknowledges Saitama's strength, having been among the few heroes who were still conscious during the conflict with the awakened Garou, whilst also feeling that Saitama needed a proper teacher in order to show him how to fully hone his strength. In order to do so, he visited Saitama at his apartment but when Saitama opened him the door, he immediately slammed it before Flashy Flash could properly introduce himself. When King asked Saitama why he did so, Saitama said that it was because "he looked annoying". Flashy Flash however wasn't ready to accept a no and ordered Saitama to open the door, because otherwise he would break it open. Before he could do so however, he was interrupted by Genos, who demanded to know what Flashy Flash was doing in front of his masters apartment, though Flashy Flash told him that it was none of his business. They started an argument, which eventually turned into a fight that was stopped by Saitama however. Genos than asked Saitama if Flashy Flash was an acquaintance of him, to which Saitama replied with a haltingly yes. He then introduced Flashy Flash to Genos but said his name wrong, calling him "Forelocks in the face". Flashy Flash told Saitama that this was just the nickname Saitama gave him earlier and vouched to change this attitude of his. When King tried to tell Saitama Flashy Flash's correct name, the hero stopped him as he wanted that Saitama remembers it himself, because otherwise he would never learn. Genos then asked if he should eliminate him, but Saitama told him not to, because he would only end up "breaking stuff". Saitama than recalled that he was trapped underground with Flashy Flash earlier and wondered if he had saved him. Flashy Flash then corrects him and tells him that he broke his sword. Saitama asked Genos to grab some tape to repair Flashy Flashs sword but the hero shrugged it off and told Saitama to focus on recalling who he is. Saitama then tried really hard to remember Flashy Flash's name and was able to recall the first four letters but then ended up spelling it out wrong again, calling him "shoulder blade crush", much to Flashy Flashs annoyance. He then changed his mind about his sword getting repaired and asked Saitama if he'll repair it or if he would prefer to pay in cash for it. Saitama then started to panic and yelled at Genos to get the tape, who immediately headed out to buy some. Flashy Flash then asked King to leave as he wanted to talk to Saitama in private.

After King left, Flashy Flash told Saitama his real hero name and asked him to become his disciple, as his athletic abilities were already overflowing with potential and needs proper instructions to make it shine, since he's not even using half of it in battle. Flashy Flash then wanted to start the training immediately and told Saitama to follow him, but as soon as he left the apartment, Saitama slammed the door again. Flashy Flash, now at the edge of his patience, returns into Saitama's apartment and tells him to stop messing, since he hates stupid pranks. He then tells Saitama that the other S-class heroes are useless and that the hero association needs heroes like him (Flashy Flash) who can take out monsters quick and reliable. He also tells Saitama that he's still growing in terms of strength and that with the right training, he could become nearly as strong as him. Saitama however said that he won't get along with Flashy Flash since he always called him by his hero name earlier. Flashy Flash then agreed to call Saitama by his actual name and offered him a deal: When he defeats him in a sparring match, he wins but if he loses, he has to become his disciple.

Saitama agrees and they head out to an training site of Flashy Flash. Flashy Flash than tells Saitama that in order to win he needs to land only one hit on him and that the time limit will be 30 minutes. In order to give Saitama a little advantage, he laid down all of his weapons. When the battle then started however, he almost lost immediately when Saitama suddenly appeared in front of him and almost grabbed him, with him only beárely being able to dodge his move. Flashy Flash than remembered himself that he needs to be more careful since Saitama already fought toe-to-toe with Garou.