Flashy Flash/Synopsis

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
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.