Boros, also called Lord Boros by his subordinates, was the leader of the Dark Matter Thieves, a group of alien invaders responsible for the destruction of A-City and the main antagonist of the Alien Conquerors Arc. Like Saitama, Boros faced a self-imposed existential crisis, having become so powerful that no battle thrilled him. His intergalactic travels in search of a worthy opponent led him to Earth, where he was killed by Saitama. Boros acts as a reflection of Saitama, while Saitama has become the strongest hero, Boros is the strongest villain, with not even Boros being able to thrill Saitama in battle.
This dropdown contains the synopsis of Boros’ story. Read at your own risk as you may be spoiled otherwise!
The Dark Matter Thieves appear above A-City and bombard it with shells, destroying 99.8% of the city in an instant. The only structure left standing is the Hero Association headquarters. Saitama, who was in the building, breaks into the spaceship and kills Groribas and Geryuganshoop, two of Boros's top subordinates, much to the alien's surprise. Saitama then confronts Boros.
Face to face with Saitama, Boros explains that he traveled to Earth because of a prophecy that foretold of a worthy opponent there. He attempts to goad Saitama into fighting with him. Suddenly, Saitama punches him into a pillar and berates him for destroying A-City for a stupid reason. Boros, much to Saitama's surprise, survives the hero's punch and stands up. With his restraining armor now destroyed, Boros unleashes his true strength and prepares to fight the hero.
Boros and Saitama engage in an intense fight. Seeing Saitama is unfazed by his attacks, Boros uses his trump card, Meteoric Burst and continues his assault on Saitama. He finishes his attacks with a knee that launches Saitama to the moon. Soon, Saitama jumps back from the moon, landing right on the ship. Upon the hero's return, Boros is surprised but also excited, and he charges at him with a barrage of attacks. Although Saitama is initially not moving, he soon counters with a normal punch that knocks him back before attacking him with his Consecutive Normal Punches, tearing Boros into pieces. However; his regenerative ability allows him to re-form almost immediately.
Eager to end the fight, Boros decides to use his final attack, Collapsing Star Roaring Cannon, to annihilate Saitama and the planet's surface itself. Before the blast hits the planet, Saitama uses his killer move, Serious Punch to repel it and critically damage Boros. Defeated and incapable of regenerating from the heavy damage, Boros compliments Saitama for the splendid battle. Although Saitama agrees with him, Boros replies that the hero was lying and that he had strength to spare, stating that the prophecy he had gambled on was unreliable as Saitama is too powerful. Boros then passes away while a victorious Saitama leaves the ruins of the spaceship.
Power Release: Because of his enormous strength, he usually wears an especial armour that seals his power. When he takes off his armor, his true power is released.
Regenerative Powers: By concentrating energy and boosting his healing factor, he can recover from a near-death injury in seconds.
Meteoric Burst: Using the energy released from his body as a propelling force, he is able to surpass his limits and achieve extreme speeds, delivering meteoric levels of destructive power. He can control the latent internal energy into his body and do things like send someone flying to the moon at fast speeds.
Energy Bullets: Condensing the enormous energy in his body and shooting it out through his eyes. Turning a large area into dust in an instant. This is one of Boros' special techniques.
Collapsing Star Roaring Cannon: Boros notes it as his finishing move[86], where he releases all of his energy into a single beam that he claims will blow one away along with the planet surface.
Other
Standard Tactics
Armored: We have not seen Boros fight with his armor on as Saitama destroys it with a single punch, though with what he implies to Saitama, he has never had to take it off for any of the fights across the universe. Though it's likely it would be similar tactics to his armor-removed state, merely with weaker attacks.
Boros' original design (left) and redesign (right)
In the first release of the manga, Boros looked more human and had a steel-plated looking armor with a skull ornament. His design was later redrawn by Yusuke Murata in order to look more alien.
The origin of Boros' name is from a game ONE played. It could be a reference to Ballos, the true antagonist of Cave Story, who shares the same Japanese name.
ONE has stated that Boros' disaster level is "Dragon or higher," but did not outright say God. A similar statement was also made about Orochi's disaster level by Murata.
Boros is one of the few opponents that has deduced Saitama's immense power without first underestimating him based on appearance, the other two being Carnage Kabuto and Orochi. This is likely due to Boros' ability to sense one's power and aura.
Scrapped concept for a transformation past Meteoric BurstMurata wanted to give Boros another transformation past Meteoric Burst before unleashing Collapsing Star Roaring Cannon. The idea was abandoned because that would imply Boros was still holding back in Meteoric Burst, which was not the case, as he was already going all out[101].
In the anime, Boros' fight against Saitama presents many similarities with Saitama's dream fight against the Subterraneans in terms of poses and the heartbeat, creating a connection between the first and the last episode of the season. This further highlights how Boros can relate to Saitama's existential crisis and felt the exhilaration of a real fight like Saitama in his dream. Ironically enough, Boros got his wish for a real fight, though it was against someone far too powerful for him to even faze.
One of Blast's companions bears a strong resemblance to Boros and may be the same species as him.
↑Q: Murata sensei, here's a question from overseas, can Geryuganshoop actually create black holes by manipulating gravity? It seems like they care about this a lot. A: hm~, I'm not sure. Black holes seem too powerful. I won't know for sure without asking ONE. But his ability to control flying objects should be above Tatsumaki, because he can eliminate the friction between rocks and air. If Tatsumaki throws rocks like he does, her output will be too powerful, the temperature increase due to friction and pressure, and evaporate the rocks in an instant. Geryuganshoop's psychokinesis can eliminate the friction between objects and air, the rocks will fly at sub-light speed*, that's the setting I based my drawing on. Tatsumaki can throw very large objects, but there's a limit to how fast she can throw them. Geryuganshoop is the greatest psychic in the universe after all. That's what I think. (he repeats this several times) Murata: Saitama still beat him with a casual stone throw though. In Saitama's eyes rocks at sub-light speed is nothing, it's like a bad joke. T/N: The Japanese used here is 亜光速, can mean sub-light or near lightspeed. Murata says Geryuganshoop being the greatest psychic in the universe in a joking manner.