Timeline of Events

This page is meant to catalog all major events in the One-Punch Man universe in chronological order.

Before the series
Date	Fights, Battles & Events	Image
Approx. 21 Years Prior	Tatsumaki is sent off to be tested because of her extraordinary powers.	File:Webcomicspoiler.jpg
Approx. 20 Years Prior	Boros and the Dark Matter Thieves begin their journey to planet Earth after receiving a prophecy stating that they will find a worthy opponent for Boros there.
Approx. 18 Years Prior	Tatsumaki is saved by Blast.	File:Webcomicspoiler.jpg
Approx. 13 Years Prior	Saitama enters Middle School and is beaten by Piggy Bancon. Mumen Rider attends the same school and is beaten by some delinquents.
Approx. 12 Years Prior	15 years old Superalloy Darkshine begins his daily lifting training after receiving weights for his birthday.	File:Webcomicspoiler.jpg
Approx. 11 Years Prior	Gouketsu wins the first Super Fight tournament.	File:Gouketsuhuman.jpg
Approx. 10 Years Prior	Zombieman escapes from the House of Evolution.	File:Webcomicspoiler.jpg
At most 7 years ago	Psykos looks into the future. Psykos experiments with Mysterious Beings. Gouketsu fights Orochi and loses, then eats a monster cell.	File:OrochivsGouketsu.jpg
Approx. 4 Years Prior	Genos' town and family are destroyed by a mad cyborg. Dr. Kuseno saves Genos, and transforms him into a cyborg.
Approx. 3 Years Prior	Saitama saves a young child from Crablante which began his childhood goal of becoming a hero, and begins his training. Sometime after the event, Agoni founded the Hero Association.	File:Saitama vs. Crablante.png
Approx. 2.5 Years Prior	S-Class is created.
Approx. 2 Years Prior	Elder Centipede is defeated by Blast.
Saitama's 300th day of training	Saitama defeats Himawari, and later Personification Of A Light Pull Cord.
More than 1.5 years prior	Saitama defeats Octopus Claw Man and saves King.
More than 1.5 years prior	Saitama's hair begins to fall out. 170,000-Year Magicicada Nymph attacks Z-City, but is killed by Saitama.
More than 1 year prior	Metal Bat is promoted to S-Class, and receives his signature metal bat.
Less than One Year Prior	Garou beats up and incapacitates his fellow disciples and is promptly expelled from Bang's dojo.
Six Months Prior	Garou steals the identity of Wolfman, and uses his identity to win the Super Fight Tournament. His victory earns him the attention of Suiryu, a famous martial artist and previous 4-time winner of Super Fight.
Less than One month Prior	Homeless Emperor obtains his powers from God.	File:Webcomicspoiler.jpg

Present series
Date	Fights, Battles & Events	Image
Present	Saitama has now become a powerful hero for fun, capable of killing monsters in one punch. Saitama saves cities from Vaccine Man, Marugori, Super Custom YO649Z Mk. II and the Subterranean King. B-City is destroyed.	File:Saitama kills Marugori.png
Next Day	Saitama meets Genos, saving him from Mosquito Girl. Dr. Genus orders his minions to bring Saitama to the House of Evolution.	File:Mosquito Girl killed by Saitama.png
1 Week Later	Genos begins his tutelage under Saitama's guide. Soon after, Saitama's apartment is attacked. The duo infiltrate the House of Evolution's headquarters and combat Carnage Kabuto and destroy him. Dr. Genus' life is positively changed after Saitama's actions.	File:One Punch Man 3 - 37.png
1 Day Later	Hammerhead and the Paradise Group begin their attack, but are defeated by Speed-o'-Sound Sonic and Saitama. Saitama meets Sonic and defeats him.
1 to 2 Days Later	Saitama and Genos attend the Hero Association exam and pass. Genos becomes an S-Class hero, while Saitama becomes a C-Class hero. Sneck attempts to fight Saitama but is defeated. Genos and Saitama spar and Saitama is overwhelmingly victorious.
7 Days Later	Saitama encounters Speed-o'-Sound Sonic during his search for a criminal in order to accomplish his weekly hero quota. Saitama quickly dispatches him and is promoted to C-Class rank 342. Golden Ball and Spring Mustache are sent to investigate Z-City's ghost town, where they encounter Kombu Infinity who defeats them.
Unknown	A giant meteor heads towards Z-City. S-Class hero Metal Knight and Genos fail to stop it, but Saitama manages to shatter the meteor, though he is unable to prevent collateral damage to the city.
3 Days Later	Tanktop Tiger and Tanktop Black Hole accuse Saitama of taking credit for the S-Class heroes' role in destroying the meteor, and challenge him to a battle.	File:Tanktops.jpg
Several days after	Deep Sea King and his Seafolk begin their invasion of the surface world, starting with J-City, many heroes failed to defeat the Deep Sea King Sonic and S-Class hero Puri-Puri-Prisoner escape prison, and encounter the Deep Sea King.	File:Cclan.png
Hours Later	The Deep Sea King finds the shelter and later fights Genos and defeats him. Mumen Rider arrives to stop the Sea King, and gives a speech acknowledging his lack of power. Saitama defeats the Sea King with ease and pretended to be a cheat in order to rally support for the defeat heroes, which worsened his reputation.
1 Day Later	Saitama is promoted to Rank 1 in C-Class and then decides to move up to B-Class. He now has to start from the bottom of B-Class Rank 101.	File:Int.png
Unknown	Shibabawa foresees a great tragedy that will result in the Earth's destruction. She develops a coughing fit and dies choking on a cough drop she swallowed. Saitama is promoted to B-Class Rank 63.
Unknown	All S-Class heroes are called to the Hero Association for an emergency meeting. All the S-Class heroes except Blast and Metal Knight show up to the meeting where it is revealed by Sitch that the earth is in great danger.	File:S-class.jpg
	Boros and the Dark Matter Thieves arrive to A-City, destroying it. Iaian loses his left arm against Melzalgald. Melzalgald is killed by the combined efforts of Metal Bat, Puri-Puri-Prisoner, Atomic Samurai, and Silver Fang.
	Saitama confronts the leader of the Dark Matter Thieves, Lord Boros and they began to fight. Boros uses "Collapsing Star Roaring Cannon" to destroy the planet, but Saitama counters the attack killing Boros.	File:Theend.jpg
1 Day Later	Tanktop Master trains to prove his strength can compete with Tornado of Terror's psychic powers. After being humiliated by Metal Knight, Tanktop Master trains to surpass Metal Knight's machinery as well as Tatsumaki's psychic powers.
1 Week Later	Metal Knight rebuilds A-City and turns it into an unbreakable fortress. The monster Pluton attacks Y-City and Z-City, but is destroyed by Saitama.	File:Hq.jpg
Unknown	G4 attacks King, but King runs away and Genos fights in his place. King is revealed to be a fraud and inadvertently took credit for defeating 5 monsters that Saitama defeated.
Unknown	Sitch holds a meeting in an attempt to recruit criminals to help deal with the monster uprisings. Garou attends this meeting, defeats three heroes and all of the criminals there declares his hero hunt. Blizzard of Hell tries to convince Saitama into joining the Blizzard Group, but fails. Speed-o'-Sound Sonic fights Genos to a draw. Garou defeats Mumen Rider, the Tank Topper Army, Charanko, Golden Ball and Spring Mustache on his hero hunt.
Unknown	Saitama decides to join the Super Fight Tournament under Charanko's name. Garou attacks Saitama, who he believes to be a hero searching for him and is defeated.	File:Onechopman.png
1 Day Later	Metal Bat is assigned to protect Narinki and his son Waganma from Garou. He confronts 4 Demon level threats and defeats them.
Hours Later	Elder Centipede attacks S-City and Metal Bat attempts to stop him, but ends up fighting Garou. Meanwhile the Monster Association begin their invasion. Metal Knight arrives in an attempt to defeat Elder Centipede but fails. The monsters kidnap Waganma.
Hours Later	The Super Fight tournament begins, with Saitama being in the semi-finals along with Volten, Choze and Suiryu. Genos eliminated all the monsters in C-City, but was defeated by Gouketsu.
Hours Later	Do-S encounters Blizzard of Hell and the Blizzard Group Do-s' uses Fubuki to draw out Tornado of Terror.
Hours Later	Child Emperor and Pig God fight Eyesight. Drive Knight goes around killing monsters and interrogates one for info about the monster invasion. Garou fights Watchdog Man.
Hours Later	Flashy Flash fights Hundred-Eyes Octopus, but Tornado of Terror intervened and killed it. Atomic Samurai and his students decide to strike the Monster Association. Saitama came into the finals of the Super Fight, where his disguise was blown and is disqualified. Gouketsu traps all the Martial Artist and holds the Super Fight Stadium hostage. Rosie, Choze, Benpatsu, Hamukichi and Volten become monsters. Rosie is killed by Choze.
Minutes Later	Suiryu kills Choze, Benpatsu, Hamukichi and Volten. Gouketsu smashes Suiryu into the ground. The Three Crows are killed by Sneck, Suiryu and Lightning Max. Bakuzan is transformed into a monster and pummels Suiryu. Nyan transforms several prisoners into monsters. Puri-puri Prisoner crushes Free Hugger. Saitama kills Bakuzan and Gouketsu. Watchdog Man defeats Garou. Garou attempts to fight King but is defeated by Saitama. Armored Gorilla defeats Marshall Gorilla and Zombieman follows Armored Gorilla.
Hours Later	Drive Knight enters Z-city and loses contact with Hero Association staff. Atomic Samurai and his three disciples search and destroy monsters while looking for the Monster Association's hideout.	File:Atomic and disciples.png
Unknown	Sonic receives an invitation for the Monster Association from Hellfire Flame and Gale Wind. Sonic eats a Monster Cell but fails to transform.	File:Cook 3.png
1 Day Later	Death Gatling leads an ambush with Stinger, Smile Man, Chain'n'toad, Wild Horn, Glasses, Shooter and Gun Gun against Garou. Garou defeats Death Gatling's ambush but is then intercepted by Genos. Monsters are sent to rescue Garou but Bang and Bomb arrive to reinforce Genos. Meanwhile Saitama and King are playing video games until the distress signal from Glasses causes them to move out. Phoenix Man swoops in to save Garou while Elder Centipede causes a diversion. Genos confronts Elder Centipede and ultimately loses. King draws away Elder Centipede and Saitama kills Elder Centipede.
Hours Later	Hero Association staff has a meeting discussing Monster outbreak and Garou. Zombieman discovers the location of Dr. Genus' new hideout Child Emperor investigates the location of the Monster Association hideout. Metal Knight warns Child Emperor not to trust others. Saitama, Genos, Bang and Bomb rest in Saitama's apartment. Saitama leaves to hunt Garou and buy cabbage. Narinki sends his private squad to save his son.
Hours Later	G5 captures Narinki's Private Squad and tells Gyoro Gyoro that he was sent by The Organization. Garou is assigned the task of killing a hero within a day to prove his allegiance to the Monster Association. Monster ruling parade occurs. Garou dine and dashes. Garou saves Tareo from bullying and gets knocked out by Saitama. Garou battles Royal Ripper and Bug God. Zombieman confronts Dr. Genus about the disbanding of the House of Evolution and discovers the limiter theory. Garou loses due to Sludge Jellyfish taking Tareo hostage. Tareo is kidnapped by the monsters.
Hours Later	Royal Ripper and Bug God report to Gyoro Gyoro on Garou. G5 recovers Metal Knight's head. Tareo is imprisoned with Waganma
Hours Later	Garou awakens and heads back to the Monster Association hideout. Silver Fang and Demon Cyborg are removed from operation of saving Waganma. Saitama, Genos, Bang, Bomb, Fubuki and Dr. Kuseno have hotpot.
Next Day	Garou infiltrates Monster Association and kills any scouting monster. King awakens at Saitama's house and heads home. Outside his home, he is escorted by Hero Association staff to the HQ. Puri-puri Prisoner, Pig God, Superalloy Darkshine, Flashy Flash, Tornado of Terror, Atomic Samurai, Child Emperor, Zombieman and Sekingar plan their attack on Monster Association. Garou saves Tareo and kills Royal Ripper.
Minutes Later	Garou and Tareo encounter and escape Overgrown Rover. Garou battles Showerhead, Unihorn and Super Mouse. All three monsters are killed when they anger Overgrown Rover. Garou battles Overgrown Rover and is sent to the bottom floor where Gyoro Gyoro resides. Gyoro Gyoro explains her experiments into Mysterious Beings. Garou battles Orochi and is completely overwhelmed. Saitama finds a manhole leading to the Monster Association's base.
Hours Later	Sweet Mask masks interrupts the S-Class meeting and antagonizes Flashy Flash, Tornado of Terror and Zombieman. King arrives to the meeting. Various other heroes are flown to the Hero Association HQ. King informs Bang and Bomb about the situation. Fubuki, Genos, King, Bang and Bomb meet at Saitama's Apartment. Genos stays to wait for Saitama. The rest heads towards the Monster Association's base. Saitama is exploring the tunnels of the Monster Association's base.

Trivia

• In the Original Webcomic, Saitama became a professional hero 65 days ago. In 43 days became a B-Class hero and is currently 2 days in A-Class.
• Approximate timeline of Saitama's promotions:
  • Week 1: C-Rank 388 (Saitama registers as a hero)
  • Week 2: C-Rank 342 (Post Sonic)
  • Week 2: C-Rank 5 (Post Giant meteor)
  • Week 3: C-Rank 2 (Pre-Seafolk invasion), then C-Class Rank 1 (After Deep Sea King incident)
  • Week 4: B-Rank 101 (Promotion)
  • Week 5: B-Rank 63 (At S-Class meeting)
    • B-Rank 33 (After Dark Matter Thieves' invasion, between King Arc and Garou Intoduction)
  • Week 6: B-Rank 7 (When Fubuki visited Saitama)
  • Currently in Week 7-8