Boros

Lord Boros (ボロス, Borosu) is the leader of the Dark Matter Thieves, a group of alien invaders who attacked and destroyed A-City.

Appearance
Lord Boros is a slim, cyclopean alien with lightly colored spiky hair and pointed ears, which are adorned with multiple earrings. His face is covered with crack-shaped markings that start from his eye(and cover most of his body presumably). In the area of his body below his chest, there seems to be another eye, which moves in synced with his original one. At first, he is seen wearing a full body armor that suppresses his powers. When the armor is broken by Saitama's punch, he attains a more intimidating and slightly more muscular build, while his skin darkens in color, parts of his body grow scales and spikes, and his markings start emitting energy, and gain a lighter color. In his Meteoric Burst form, his appearance changes drastically. His hair grow reaching his back, his eye's sclera becomes black, and his body becomes engulfed in energy, while his markings now return to their original, dark color.

Personality
Thanks to his amazing powers, Boros is both arrogant and prideful. Due to his love of battles and inability to find any opponent who has been able to match him in power, he roams the universe looking for worthy opponents.

History
20 years before the start of the series, while Boros was laying waste throughout the universe looking for an opponent that would be able to stand against him, he met a prophet that revealed to him that in a far off planet he would finally find a strong opponent that would be able to fight on par with him, giving Boros the enjoyable fight he had always desired.

Alien Conquerers Arc
Boros first appears with his spaceship in A-City commanding a mysterious group of alien invaders and, without an apparent reason, he completely destroys the city with the sole exception of the Hero Association's headquarters due to its high resistance to damage. Saitama, who was in the building, then broke into the spaceship and effortlessly eliminated Gloryverse and Geluganshp, two of Boros' top subordinates, much to his surprise.

Face to face with Saitama, Boros starts explaining him that he attacked A-City because of a prophecy that foretold he would find a worthy opponent. Annoyed, Saitama punches Boros, berating him for destroying A-City for a stupid reason. Unexpectedly, Boros survived Saitama's lethal punch and with his armor destroyed, he unleashed his true strength and prepares to fight a surprised Saitama, going all out.

During the battle, Boros hits Saitama with everything all of his power, including his trump card: the "Meteoric Burst" ability, and without caring for his star ship, attacks Saitama continuously before he can even react, kicking him all the way to the moon. Saitama returns by jumping from the moon and begins to counterattack; hitting Boros with a barrage of punches. Even after being reduced into pieces, Boros' regenerative abilities are so strong that he recovers almost immediately. Eager to end the fight, Boros decides to use his other trump card: the "Planet Buster Roar Cannon" but before the beam could hit the planet, Saitama used his own trump card: the "Serious Series Punch" which repels Boros' beam and critically damages him. Defeated and incapable of regenerating from the heavy damage, Boros compliments Saitama for the splendid battle.

Boros' last words show that he knew Saitama never showed his full potential during the battle, saying that Saitama is way too strong, and that as a result, the prophecy that he had gambled on was a lie. Boros dies while a victorious Saitama leaves the ruins of the star ship.

Abilities & Powers
As the leader of the invading force of aliens, Boros is extremely powerful. According to Boros, as an adaptation to living on a planet that have harsh climates, his species has developed the greatest regenerative ability in the entire universe. Boros also appears to be able to sense peoples' energy levels, which manifests itself as an aura around the said person.

Physical Abilities
He claims that in particular, his regeneration, physical ability and latent energy far surpasses others. Saitama even said that he was the strongest opponent he has ever fought.

Immense Strength: Boros displays extreme strength during his fight against Saitama.

Immense Speed: Boros has extreme speed as he was able to keep up with a casual Saitama.

Immense Durability: Boros is shown to be amazingly resilient, to the point of being the first opponent of Saitama to survive, after being hit directly by his punch, despite having his full powers sealed by his armor.

Regeneration: Boros has been shown to regrow an arm in seconds just by concentrating on it. When struck by Saitama's consecutive punches, he was blown apart but was able to regenerate his whole body in an instant. However Boros' regeneration ability has a limit. As it shows in the end, he lost to Saitama and was unable to regenerate again.

Energy Projection: Boros has been shown to be able to direct large blasts of energy from the eye in his chest with great destructive power.

Released Form: Boros wears an ornate suit of armor that is designed to keep his immense powers in check. When the armor is removed his body becomes black and spiky and begins to glow from the released energy.

Techniques
Trump Cards: Boros has several techniques which he uses when he wants to finish a fight quickly or thoroughly destroy an opponent.
 * Meteoric Burst:  It is Boros' trump card which he resorts to when he wishes to settle a fight quickly. He uses his latent energy to boost his body to release speed and power beyond its limit, at the cost of putting immense burden on his body. This also causes his body to start glowing white. In this form Boros' kick had enough power to send Saitama to the moon.
 * Collapsing Star Roaring Cannon: While in his meteoric burst form, Boros can launch a massive beam of energy from his mouth. Boros states that it can wipe out the face of a planet.

Quotes

 * (Referring to Saitama) "This state... It burdens my body immensely, similar to anaerobic exercise. It's supposed to be a trump card I only use to settle a fight quickly, but this man... makes me wanna go all out."
 * (To Saitama) "It's as if you didn't bare your fangs at all, during this whole battle..."

Trivia

 * It is worth mentioning that he is the first opponent of Saitama that survived after getting one-punched, much to Saitama's surprise (excluding characters like Sonic and the tank top siblings, whom he didn't mean to kill). However Boros knew all along that Saitama "didn't bare his fangs at all".
 * The origin of Boros's name is from a game ONE played.
 * Boros is the second character to have two variation points in the manga. This is for in his appearance in the manga (the first looking plain and more armored while the second version had more detail and the armor was like a second skin), and his battle with Saitama (First time was a whirlwind of punch where the gravity core was ending in the same way as they ascend to outside and on top of the spaceship, after shooting him with a laser, Boros kicks Saitama into the ship while he is in the air, then pummeling Saitama into and through a giant piece of the ship while using Meteroic Burst, then grabs said piece and throws it at Saitama. Second time (which is canon) is instead showing Saitama and Boros exchange blows across the room destroying the ground, Boros' energy blast is more detailed and destructive, he appears behind Satiama and makes a direct hit to the back of his head, and while in Meteoric Burst throws one punch at Saitama sending him flying across the ship while obliterating much of the ship below, Boros then kicked Saitama with enough power to send him to the moon).
 * It's possible that the "worthy opponent" mentioned in the prophecy to Boros was actually Garou. In an interview where ONE is questioned about who would win in a fight between Boros and Garou, ONE replies that Boros in a fight against Garou in his perfect form would be "one hell of a battle."