Sweet Mask/Synopsis

History
Sweet Mask was born with a very ugly face which he was ashamed of, and he attempted to be beautiful on the inside and adhere to strict moral principles to compensate. Three years ago, right after the formation of the Hero Association, Sweet Mask passed the entrance examination. He performed his hero activities wearing a mask to hide his face and never revealed his face in public for fear of revealing his ugliness. Nobody knew his real name and appearance, as he had stolen and destroyed the information he had entered while registering. When he was promoted to the B-Class, he chose the hero name "Secret Mask." He grew inexplicably strong as he continued his hero work.

One day, an accident broke Sweet Mask's mask during a battle, revealing his face to the bystanders. Instead of hearing boos from the crowd, he heard only cheers. He looked at his reflection in a puddle and saw that his appearance had become beautiful. He then understood that his hatred for his ugliness had caused his body and face to transform; he had become a monster.

Initially, Sweet Mask was doing his hero job with a mask to hide his face. His hero name back then was "Secret Mask" but now, after a certain event, he decided to remove it. Due to his beautiful face, his hero name is "Sweet Mask".

He wrote Ikemen Castle (イケメンキャッスル) and Ikemen Love Story (イケメンラブストーリー).

National Superhero Registry Arc
Sweet Mask gets a call from the Hero Association about Genos passing on the test and becoming an S-Class. Later, he visits both Genos and Saitama at an udon shop as they finish an eating competition, asking Genos to speak with him privately. He asked Genos how the test was with Genos replying that it was too easy and a waste of time. Sweet Mask stops Genos from attacking him, who was thinking this was a rookie beating, but he only came to congratulate Genos for reaching S-Class and tells him, that he expects great results from him and walks off. After that, he is seen in his penthouse thinking about how interesting Genos is.

Sea Monster Arc
While the Seafolk invade J-City, Sweet Mask makes a guest appearance on a television show to promote his new song. The host of the show asks Sweet Mask what he thinks about the current situation, to which Sweet Mask replies that he is only a hero when he fights evil and that currently, he is here to promote his new song as a singer. However, he goes on to say that heroes have to be tough, strong and beautiful at all times in order to ease the fear and worries of the people. He states that he finds it regrettable that there were heroes who were defeated by evil and stating heroes must improve themselves so that no hero would die in vain in the future. Sweet Mask is called in to advise about Saitama's promotion to B-Class. Sweet Mask replies that they do not need him for such a trivial task as promoting someone to B-Class and even states that he only wants a say in promoting people to A-Class and higher, as they tend to have a strong influence on the association's image. He in the end allows Saitama to be promoted. In the anime Sweet Mask appears in his dressing room along with Bearded Worker to talk about Saitama's promotion to B-Class. However, he only cares about A-Class heroes and above as they are the public face of the Hero Association, and feels disgusted because of the Deep Sea King incident, due to many A-Class and even two S-Class being defeated by said monster. The Bearded Worker then shows Sweet Mask a video of Saitama defeating the Deep Sea King in a matter of seconds. His discovery on Saitama's true potential sparked minor interest in him.

Alien Conquerors Arc
After the defeat of the Dark Matter Thieves and the fall of their spaceship Sweet Mask appears and mocks the S-Class Heroes for being unable to stop the destruction of A-City much to Metal Bat's anger. Later when they found the remaining minions of Boros while the other heroes wonder what to do with them, he mercilessly kills them saying that "evil" must be eliminated without doubts. The other heroes watch shocked and Sweet Mask lectures Genos about implementing "justice," as well as telling him how disappointed he was with the latter after the Deep Sea King incident and with the most recent destruction of A-City before he walks away. Meanwhile, Genos thought about how, before meeting Saitama, his way of thinking was similar to Sweet Mask's.

The Blizzard Group Arc
Sweet Mask encounters Suppon, a caveman test subject who escaped from his laboratory and had begun to brutally assault civilians. Sweet Mask deemed Suppon as 'evil' and informed him that he was under orders to bring him back alive, but going against these orders, he defeats and brutally kills Suppon in short order, amidst a cheering crowd.

Super Fight Arc
Sweet Mask is seen performing a concert with a band in a concert stadium, but was interrupted by large explosions, signalling the arrival of a Mysterious Being.

Despite the situation, Sweet Mask continues his show, toying with the Mysterious Being before eliminating them with a swift slice and an uppercut. However, the audience believes it was part of the show, and no further questions are asked. After the show, Sweet Mask contemplates about the Monster Association, resolving to take action himself.

Monster Association Arc
Sweet Mask arrives at the Hero Association headquarters. He finds that the assault team woefully inadequate as he expected elite members only. He opposes the presence of Atomic Samurai and his three disciples, Bushidrill, Iaian and Okamaitachi as they are too weak to take care of themselves.

Sweet Mask barges into the S-class meeting. Child Emperor tells him to lead the surface strike team to which he is against. To take advantage of his leadership skills, he should lead the underground strike team but Flashy Flash and Zombieman are against it. Sweet Mask questions Zombieman on his regeneration abilities and accuses him of being a monster. Before a fight could break out, King enters the meeting and manages to convince Sweet Mask to back down. He still insists that he is part of the underground strike force. He leaves with various other heroes to attack the Monster Association.

Sweet Mask later rescues Bushidrill from being hypnotized by Do-S' whip, when he along with Iaian and Okamaitachi were facing off against Do-S' slaves. Sweet Mask tells the three disciples of Atomic Samurai to leave the fight to him, believing it will be exceedingly simple for him.

The three disciples decide to trust Sweet Mask and retreat, leaving him alone to face Do-S and the brainwashed Narinki Squad. Do-S tells Sweet Mask that she is a fan of his, and wants to spend some time with him alone, in exchange for 'unbrainwashing' the slaves. Sweet Mask tells her that bargaining won't work against him, and instead decides to kill Do-S. He effortlessly tears through the entire Narinki Squad, mercilessly killing all of them. He continues to charge towards Do-S, who attempts to brainwash him with her whip, but fails to do so as Sweet Mask is somehow immune to such attacks. Realizing this, Do-S quickly surrenders, promising that she will obey his every command. Sweet Mask is unmoved by Do-S's pleas for mercy and kills her.

Sweet Mask is later seen exploring the underground base with the head of a monster in his hand. He stumbles upon a gigantic machine, and the monster's head explains that it was built to nurture the Monster Cells harvested from Orochi. Sweet Mask deduces that in order to completely stop the Monster Cells' production he has to kill Orochi, and proclaims that he will do so, ignorant to the fact that Orochi has already been defeated by Saitama elsewhere. He quickly destroys the machine and moves on. However, as he continues to explore the base he encounters Fuhrer Ugly. Because of Fuhrer Ugly's extremely grotesque appearance, Sweet Mask finds himself unable to fight back out of shock, and he is thrashed by the hideous monster.

Original Webcomic
Sweet Mask and Fuhrer Ugly are separated when Tatsumaki rips the Monster Association base out of the ground. Sweet Mask eventually returns to the battlefield to fight the executive monsters with the other heroes. He throws a large boulder at Black Sperm and demonstrates abnormal physical traits over the course of the battle such as being able to withstand almost lethal attacks with ease and reattaching his arm after it was shot off. Veins and scars cover his body as a result of his powers. Sweet Mask aids Child Emperor in his plan to defeat the monsters, fending off legions of the multiplying Black Sperm whilst avoiding attacks from Evil Natural Water, which impresses Pig God and Atomic Samurai.

Later he is confronted by Garou after he destroys Golden Sperm with ease, remarking on Garou's power. Garou mocks Sweet Mask's views of justice and beauty and proceeds to fight the remaining S-Class Heroes. Though Sweet Mask and the others are able to land several blows on Garou, he is able to defeat them all, striking Sweet Mask brutally across the face.

After Saitama defeats Garou, a recovered Sweet Mask yells at him to kill him and says that he cannot be allowed to live after all of his crimes. He then implores Bang to do the same, offering to carry out the execution himself. He is prevented from carrying this out by the child Garou brought with him and is outraged when he is able to escape.

Psychic Sisters Arc
Sweet Mask is in a studio pondering the thought about the beauty of strength and Saitama. He is asked by his director to look over a group of young and new C-Class Heroes named the Sugar Pop Boys who are in the entertainment industry. However, he declines, finding imitations to be 'ugly' and a waste of time. When the group insults him and challenges him, Sweet Mask is able to intimidate them with a frightening aura, forcing them to cower in fear while adamantly voicing none of them had a true beauty like Saitama, which was overwhelming power. During this time, a strange vein appears on his neck.

Ninjas Arc
Sweet Mask hosts a meeting with other Hero Association to discuss a new project called Supreme Hero Production Project that would feature Saitama.

Later, Sweet Mask finds Saitama and invites him for tea. Saitama wants a coke, but Sweet Mask orders him a glass of ginger ale, greatly annoying the bald hero.

Sweet Mask invites Saitama for lunch. He tells Saitama about his plans of turning him into a perfect hero, as he sees the potential for Saitama to become the ideal hero of the Hero Association. Saitama asks Sweet Mask why he can't become the ideal hero he was dreaming of, but Sweet Mask responds that he cannot. He takes Saitama to an amusement park ride and explains his backstory and why he is looking to Saitama to carry on his legacy. Without agreeing to anything, Saitama leaves to the spar with Genos. Sweet Mask resolves that he will not give up on Saitama. A ruckus in the amusement park crowd draws his attention, and he realizes that they are screams.