Yes and No. To put it briefly, Genos was previously killed by Garou, however, in later chapters, it is revealed that time travel is possible in the One Punch Man universe. This allows our main protagonist, Saitama, to travel back in time and defeat Garou before he can kill Genos.
For a more in-depth explanation, read the spoilers of chapters 166 to 168 below. These chapters will provide information on How Saitama Obtained His Time-Traveling Abilities? and What Happened to Garou and Saitama’s Full Epic Battle? Additionally, the highly anticipated number one S-class hero, Blast, makes an appearance in these chapters.

Chapter 166 Explained
In the chapter, Garou gains an immense power boost from god, which causes everyone in his presence to fall apart. Everyone started suffering from the effects of Garou’s cosmic radiation, including hair loss and coughing up blood. Suddenly, Blast, the hyped number one S-class hero, arrives on the scene. Blast explains that Garou has now become a god-level threat.
Garou then further reveals that he is the “Ominous Future.” — an important part to remember.
Suddenly, Genos charges forward with a headbutt, despite being in poor condition to fight. Garou acknowledges Genos’s bravery and comments that it’s not surprising that he is Saitama’s apprentice.

Blast VS. Cosmic Garou
Blast then uses his “Dimension Cannon” technique to teleport Garou to different locations while delivering high-speed punches using his “Gravity Knuckle.” Blast initially appears to have won as he teleports Garou away, but Garou’s power increases so rapidly that he can copy the ability and teleport back and delivers the same “Gravity Knuckle” punches to Blast. Garou then praises Blast but still considers him unworthy of his attention, showcasing the extent of his newfound power.
Garou Kills off Genos
Garou then picks up Genos and pierces his hand through Genos’s core before he can even say “master”, in an attempt to bring out Saitama’s full power.
On the next page of the chapter, there is a black, empty page, followed by an illustration of rain pouring down. Finally, Saitama appears, unaffected by the toxic black rain that’s pouring on his face. He has a very serious expression that has never been seen before. Garou comments, “You’re a bit late,” as he casually throws Genos’s core. Saitama catches it in his hand.

Serious Saitama Is Unleashed
The next panel displays a graphic image of Genos’ lifeless body. The only word Saitama was able to spout out is “Genos.” with a dark and frightening expression.
The page then flashes a previous memory between Saitama and Genos, in which they discussed Saitama’s ability to always arrive at the right time, to which Saitama replied “Nah. I usually arrive too late…” in which at that present moment, he was indeed late. Saitama internally reflects on not having the instincts of a hero.

We see a different side of Saitama as he becomes deeply enraged, a rage that is distinct from his previous battles with other villains, as this time Saitama has taken this fight personally.
He unleashes a devastatingly powerful punch at Garou. Garou, in response, imitates Saitama and activates “Saitama mode”. Blast becomes petrified at the prospect of the two forces colliding, as the energy released would likely cause the earth to shatter.

Chapter 167 Explained
Blast intervenes to prevent the destruction of Earth by teleporting Saitama and Garou to space before their serious punches can collide.
The two fists clash in space and create a shockwave so powerful that earth would’ve blown up completely. Humanity would’ve ended in a single punch.
Blast and his team redirected the attack away from Earth to ensure its safety. The impact of the two destroyed multiple stars and sent them flying from Earth to the moon of Jupiter as a result of the recoil.

Garou and Saitama in Space
Garou looks up and sees Saitama standing above him with the actual planet Jupiter behind him. Saitama remembers his previous battle against Boros in space, but his focus is solely on unleashing his full power against Garou.
Garou even questions if Saitama is even human due to being unfazed.
Saitama reflects on how he finally found someone as strong as himself, but surprisingly, he doesn’t feel any excitement. He attempts to store Genos’ core in his shirt, but he realizes that it might fall out if his clothes get damaged, so he decides to hold onto it.
Garou begins to ponder about their current location on one of Jupiter’s moons and expresses a concern about finding a way back, to which Saitama responds:
Shut up. That can come after I beat the sh*t out of you. Bring it on. One hand is all I need for you.
Saitama from On Punch Man
Yep folks, we finally see it happening, Saitama is furious. And we are about to witness an epic battle ahead of us.

Saitama Destroys the Moon
Garou to which replied “Later then, LOL” and attempts to teleport Saitama, using a power he copied from Blast, but Saitama kicked the teleportation away and punched Garou in the face. Despite this setback, Garou continued to fight, displaying various martial arts techniques, but they were no match for Saitama. Saitama then used the “Serious table flip” technique, easily lifting and destroying the top layer of the moon.
Garou then realized he could simply copy Saitama’s moves in an attempt to win, just as he had with Blast.

Chapter 168 Explained
Funny enough, Saitama also copies every Garou’s moves and delivers a powerful line with a stern expression:
What’s wrong? You said you were gonna copy me when I’m serious and surpass me, didn’t you? Go ahead and try. Isn’t that the whole purpose of this?
Saitama from On Punch Man
It’s as if Saitama used Garou’s own cards against him.

Saitama’s Sneeze Almost Destroyed Jupiter
The reality sets in for Garou as he realizes that no one can level with Saitama’s power which is further reinforced when Saitama nearly destroys Jupiter with just one sneeze. Yes, he almost blew away the whole planet with just one sneeze mid-fight.
Garou then sees the sun and believes he has found the answer to defeating Saitama. He teleports Saitama to the sun’s surface and returns near Earth, thinking he had succeeded in defeating Saitama. However, to Garou’s surprise, Saitama was just behind him. Garou is puzzled as to how Saitama could catch up so quickly after being sent flying in the opposite direction, but Saitama, being Saitama, explains that he used his fart to navigate through space and catch up.

Cosmic Garou’s Defeat
Saitama then delivers a powerful punch, sending Garou back to the surface of the earth in an instant. As Saitama pulls his fist out of Garou’s badly damaged face, he realizes that they have returned to the starting point of the fight.
Admitting defeat, Garou asks Saitama why he isn’t killing him yet, to which Saitama responds by reflecting on why he is a hero. He usually says that being a hero is just for fun or a hobby, but because of this mindset, he wasn’t there in time to save someone he cares deeply about, Genos. Saitama loves Genos more than he realizes, and he didn’t know that until he was gone.
Ultimately, it is because he is a hero that he must fulfill Tareo’s final request: to stop Garou without killing him. This is when Garou sees Tareo’s lifeless body. This sight brings back a glimpse of Garou’s human face; this is because Tareo is what’s left of Garou’s humanity.

Garou’s Ultimate Technique Revealed
Garou then sees the similarity between himself and Saitama, with Saitama having Genos and Garou having Tareo. He requests Saitama to replicate his ultimate technique of “his fist” which he has been trying to perfect, even after obtaining god-like powers, but has yet to achieve success.
Saitama copies Garou’s movements without knowing the outcome of it. Garou then said:
If anyone can master the power of god without taking god’s hand, it’s you.
Garou from One Punch Man
which straight up confirms that Saitama is literally a god.
The voice of god suddenly interrupts the two, saying, “Silence. I am taking them back.” and strips away the power he had given to Garou. Garou continues to urge Saitama to defeat the “Ominous Future” before turning into a body of salt.
With the ultimate technique Garou taught Saitama, Saitama was able to perform time travel.

Saitama Time Travels
Saitama travels back in time to when Garou declares himself as the “Ominous Future.” Saitama then understands what he needs to do and delivers a punch to that memory, bringing the story back to the moment when Garou was facing all of the S-class heroes, but this time he stops Garou before he can kill off Genos.
Genos is alive
With that one punch, everyone, including Genos, was saved. “Sensei!” Genos calls out, seen on a rock with only his head and torso remaining.
Suddenly, the Saitama from the future and the present connect into one to prevent any kind of temporal paradox. The same occurs with Garou. This leads to both future memories being completely erased, and Saitama is left confused about how he ended up in a different place, as the last thing he recalls is being struck by Garou’s gamma-ray burst.

Saitama then sees Genos’ core still on his left hand and screams, this time Genos headbutts Saitama to which Genos apologizes, saying that he got carried away. At the end of the panel, Saitama says:
Genos!! You scared the crap out of me! You’re still alive!!
Saitama from One Punch Man
He says with gratitude and happiness.
Fans are elated to witness Genos’ return, as many believed that Chapter 166 marked the end of his journey. The rest of the chapter remains a mystery to be discovered, but one thing is for sure – the happy reunion of Saitama and Genos has filled the hearts of fans with joy and satisfaction.
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