Saitama vs. Orochi

You... do not appear to be useless trash that can be ignored... Saitama vs. Orochi was the battle between the B-Class hero Saitama and the leader of the Monster Association, Orochi.

Prelude
After being defeated by Tatsumaki, Gyoro Gyoro calls out to Orochi to save him but to no avail. He wonders why Orochi is not coming to assist him, for he managed to obtain absolute control over him from years of brainwashing during his transformation into a monster. Unbeknownst to him, Orochi took notice of Saitama being able to defeat Overgrown Rover. Orochi says he does not know how Saitama managed to get in, but he can tell that Saitama is not useless trash that can be ignored.

Battle
Orochi and his dragons on his left hand strike with the newly-learned Water Stream Rock Smashing Fist. However, Saitama manages to kill all of the dragons with his punches. Orochi's dragons on his right hand fire several beams of energy. The force of the dragons combining their energy beams creates a huge blast, as well as creating several lightning bolts. Throughout the Monster Association Headquarters, these bolts of lightning strike several heroes, such as Atomic Samurai, who blocks the bolts with his sword, Bang and Bomb, who redirect or destroy the bolts with their respective martial arts, and Tatsumaki and Gyoro Gyoro, who protect themselves with psychic barriers. The energy blasts also elevate the terrain below Z-City and cause the buildings to rise, as well as destroy many other buildings in the process.

While this is happening, a train on the metro system feels the shockwaves of the attack. The conductor of the train puts the brakes on the train and notices the huge circular path in front of them that destroyed the train track. They also notice a figure blur past them, that figure being Saitama, who is running towards Orochi. The hero then jumps up and prepares to strike Orochi's head with a single punch. The Monster King uses some of his dragons to try and stop Saitama, but Saitama destroys all of them. Orochi and his remaining dragons prepare to finish Saitama with a combined attack and release a combined energy blast that goes downward. Unfortunately for Orochi, Saitama manages to power through the energy blast and punches Orochi, destroying the monster's body. As Orochi's head and his broken body are floating in the air, Orochi asks Saitama what he just used. Saitama replies that it was simply a normal punch. As Orochi's head and the rest of his body fall down the pit, the monster realizes that at that moment, he is feeling terror. Saitama watches from a ledge as Orochi falls down to his defeat, making the bald hero the victor once again.

Aftermath
Gyoro Gyoro sends one of his eyes to look for Orochi only to find his remains, confirming his death. When looking for the hero that killed him, he sees Saitama who mistakes his eye for a bug and crushes it by clapping his hands together. When Gyoro Gyoro notes on Saitama's bald appearance, Tatsumaki wonders if he is referring to Superalloy Darkshine, giving him the credit for Orochi's defeat.