Tomura Shigaraki (死柄木弔 Shigaraki Tomura?), born as Tenko Shimura, is the primary antagonist of Boku no Hero Academia. He is the acting leader of the League of Villains and desires to destroy the society that All Might represents by killing him, so he create a new one in his own image. He is secretly the grandson of Nana Shimura, All Might's deceased mentor and the 7th wielder of One For All.
Tomura Shigaraki is a skinny young adult. He has light colored skin and hair. He has straight hair and Disguised as a villain, Tomura wears a mask in the shape of hand that conceals a great portion of his face and a dark colored costume. As a civilian, Tomura does not wears a mask or his costume but is seen in average civilian clothing.
Like most villains in Boku no Hero, Tomura is disgusted with how society is like. He also hates the heroes especially All Might for being the symbol of peace. Tomura also hates anyone who admires All Might like Izuku Midoriya and Hero Killer Stain. Unlike the Hero Killer, Tomura is out for carnage and to some degree fame. At times, Tomura can become furious over anything that happens to not go his way like how he did not get any recognition for the Noumus that attacked the civilians in Hosu or for people constantly praising the Hero Killer in front of him. Tomura is also arrogant and sadistic. He has no qualms in threatening anyone's life whether it is a civilian or a student at Yuuei.
Tomura has a quirk called decay that allows him to turn any solid object that is within his reach to dust. When he touches an object with his hands it will disintegrate and turn into dust. With this particular quirk, Tomura has to be within a short distance of his target to grab onto them or even make contact with them to actually damage them. With this quirk, he can turn any object to dust instantly.
Tomura is also strategic and can plan highly skilled attacks such as the planned attack on the Yuuei students by the Vanguard Action Squad.
Tomura is perceptive of his opponents abilities and is able to react swiftly against them. Tomura is knowledgeable about the heroes and even other villains such as All Might, Chizome Akaguro, and Chisaki. In addition to his intelligence, Tomura have fast reflexes as he is able to react to an attack from his opponent. Like other powerful villains. Tomura posses a decent amount of stamina as he was able to sustain damages in the battles he fought against the heroes.
Overall, Tomura Shigaraki is a powerful villain. He was able to fight head on with Eraserhead with no struggle, and was even able to damage him. He also has control of his subordinates in the League of Villains, due to his position as one of the leaders.
Tomura and the other villains first appeared at the training site where the students were practicing. When he did not see All Might, he was frustrated and decided to use his force to attack all the other heroes there as a way to draw All Might's attention. He fought Shouta and was responsible for defeating him. He also tried to attack the students but All Might eventually appeared. Shocked at All Might's appearance, he tried to attack him as well but as time dragged on more heroes appeared. Tomura decided to retreat with one of the other villains. While they were able to retreat, he complained to one of his men that they were unsuccessful in their objectives to take out All Might and ended up losing their men. He was instructed by an individual on a computer monitor to start looking for new men for the organization.
He watched the Sports Festival on his computer and was carefully observing Izuku during the event.
After the Sports festival, he met with the Hero Killer Stain. He decided to let him join the League of Villains since they were in desperate need of a new member. The two then got into a skirmish where Stain pinned him down. After discussing the values of the League of Villains, Stain asked to go to Hosu to continue his work. Black Mist then teleported Tomura, Stain and himself to city of Hosu. As Stain took off to try and cleanse Hosu of the "fake" heroes, Tomura began complaining about Stain and his motives. He decided that he wanted to unleash a few Noumus upon the town to destroy it. As the Noumus were getting defeated by the heroes and Stain fell in battle against a few heroes, Tomura got infuriated and decided to leave the town. The next day, he read the news and was frustrated that Stain got recognition from fighting the heroes and that his Noumus did not get any recognition from the media.
He was introduced to new members of the League of Villains. Tomura was not impressed by their praise of the Hero Killer and left the room out of spite. Tomura later decides to confront Izuku at a public mall in his civilian appearance. He took the teen as hostage and asked him a couple questions about himself and the Hero Killer. When Izuku states that his and the Hero Killer's motives were because of the inspiration of All Might, he decides that he is more willing to kill All Might since he is praised so much as the symbol of peace. He decides to leave when Izuku's friend questions him. He left the mall thinking about his grudge against All Might.
Tomura commissioned the Vanguard Action Squad to attack the Yuuei students at night when they were on their summer school trip to enhance their powers. He ordered them to capture Katsuki Bakugou and placed a hit for Izuku Midoriya and other students at Yuuei Academy. The attack ultimately resulted in many students getting minor to major injuries (some of which would have to get hospitalized), Katsuki and Ragdoll getting captured, and the trip coming to an abrupt close.
Tomura wanted Katsuki to join the side of the villains. He was a bit frustrated when Katsuki declined his offer and states that All Might was his hero and that he would always support him. Tomura decided that he did not have time to deal with Katsuki's defiance and sought power from his master to convert him to the dark side. As he was about to attack Katsuki, All Might and the other heroes broke in to rescue Katsuki. At the sight of All Might's appearance, Tomura recalled his past and yelled at All Might out of spite. Tomura's master took each of the villains and Katsuki with a black sludge substance and teleported them to a destroyed warehouse on the other side of town.
As Tomura's master tried to fight All Might who came to save Katsuki. Tomura tried to capture Katsuki again but he was saved by the combined efforts of Izuku, Tenya, and Eijirou. Tomura's master decided to teleport Tomura and the rest of the villains away from the area where he was fighting All Might for their safety. His master told him that he should continue his plans. When his master was defeated in his fight against All Might, Tomura was furious.