Garou vs. Flashy Flash vs. Platinum Sperm

I'll take on anyone who wants a fight. Absolute Evil is unbiased, you know. Heroes, monsters, I will slaughter every last one of them, and rise up to become the ultimate symbol of fear... Disaster level "God". Now bring it on.

Garou vs. Flashy Flash vs. Platinum Sperm is the three-way fight between Garou, the S-Class hero Flashy Flash, and Platinum Sperm.

Prelude
Having been teleported to the surface, Flashy Flash notices that Garou is around and suddenly throws a kick at the Hero Hunter, who manages to narrowly avoid his kick. They begin talking and after they both know each other identities, Platinum Sperm interrupts them by passing through the two and simultaneously pummeling them. Platinum Sperm goes on by saying that he is disappointed that despite having monsterized so much, Garou still doesn't have the courage to join the monster side. Flashy Flash and Garou stand up, completely unfazed by the earlier attack, and they both claim that they are going to thrash the other two. The free-for-all battle starts as Garou says "Bring it on!"

Battle
Platinum Sperm and Flashy Flash charge towards Garou, who then jumps up high, causing the other two to cross blows against each other. To their surprise, Garou quickly jumps downwards them with a mighty double kick, with Flashy Flash and Platinum Sperm dodging and the ground being broken apart along with sending many rubbles flying due to Garou's stomp. As many rubbles are floating in the air, the three of them begin exchanging blows at incredible speeds, while using the rocks as platforms.

The fight is happening so fast that a geometric structure of light is created from the speed of their fight. Flashy Flash charges at Garou but is quickly knocked back by the latter. Platinum Sperm instantly uses his tentacle to restrain Flashy Flash, holding him still by wrapping it around his neck and striking him repeatedly, causing the hero to spit blood. Flashy Flash tries to counter with his Wind Blade Kick but Platinum Sperm manages to dodge his attack. Platinum Sperm then suggests Garou team up with him to defeat Flashy Flash, pointing out that the hero's been weakened due to losing his sword and saying that they can have a one-on-one battle immediately after beating him. As Garou pretends to agree with him, Platinum Sperm lets his guard down and is punched in the face by the Hero Hunter, much to his anger. While their fight continues, Garou begins to showcase his Monster Calamity God Slayer Fist, and momentarily repels both him and Flashy Flash.

As the battle goes on, Platinum Sperm punches Flashy Flash but he manages to block his punch, although the impact still sends him flying backward into a rubble. Garou immediately appears behind Flashy Flash and attempts to kick him, but the hero manages to evade. As he starts to get overwhelmed, Flashy Flash is in disbelief, thinking that in a single day, he has encountered four people (Saitama, Blast, Garou and Platinum Sperm) who have surpassed his supposedly unmatched speed, and this fact hurts his pride deeply. Flashy Flash is enraged and charges at Platinum Sperm with his Flashy Fist, landing multiple punches on him. However; Platinum Sperm uses his Platinum Rings, rotating both of his arms and his tentacle to defend himself, warding off punches from Flashy Flash. While catching his wrist, Platinum Sperm talks to him, commenting that he now knows Flash's limits as a mere human before kicking him away. Flashy Flash is frustrated and switches to attacking Garou with his Flowing Shadow Feet. Unfortunately for him, Garou simply deflects his kick away, which seems to upset Flashy Flash. At this moment, Platinum Sperm comes in and kicks Flashy Flash hard in the face while remarking that the hero is full of openings and asking what is wrong with his spirit. As he proceeds to viciously pummel Flashy Flash, Platinum Sperm likens him to Superalloy Darkshine, saying that once they are outmatched by someone in their specialty, they abandon their duties and put all their effort into protecting their own pride. After further expressing that a hero who truly wants to save weak people does not exist, Platinum Sperm finishes Flash off by punching him in the face so hard that it sends the hero skyrocketing down into ground, subsequently knocking him out.

Immediately after Flashy Flash's defeat, Platinum Sperm is engaged by Garou, and the two of them begin fighting for real, further accelerating their movements. They are able to fight each other on equal footing, with both of them creating another geometric structure of light which is denser than the one previously and exchanging multitudes of blows, within only 1.3 milliseconds in the sky before the Hero Hunter manages to punch the fusion monster in the face without him defending in time with his Platinum Rings, sending him skyrocketing into the surface. An injured Platinum Sperm gets up, becomes furious and calls out Garou. In an instant, Garou dashes through him, diving both his hands through his body, delivering a finishing blow that causes Platinum Sperm to explode into bits, making Garou victorious.

Aftermath
Immediately after finishing off Platinum Sperm, Garou is confronted by Sage Centipede and Evil Ocean Water.

Trivia

 * This is the first fight in the series where there are three separate belligerents all opposed to one another.