Nine/Synopsis

History
Nine is a villain who was born with a very powerful, almost "god-like" Quirk that allows him to control the weather, dubbed as Weather Manipulation. With his ability, he can summon destructive thunderstorms and hurricanes in an instant. He can even create powerful tornadoes that are powerful enough to rip the ground apart.

Being the possessor of such power caused Nine to become disturbed by the world's hierarchy of authority, which he considered flawed, as it's one where the weak rule the strong. So he wants to create a world where those with strong powers rule over those with weak or no powers. Over the years, Nine recruited other individuals such as Chojuro Kon, Kiruka Hasaki, and Hoyo Makihara who, like him, feel oppressed by the current failed world, and together they would try to make their dreams come true.

However, the only obstacle that prevented them from carrying out their plans is Nine's own powerful Quirk, as the magnitude of its power causes cellular damage to Nine’s body, and it would eventually end up killing him. Looking for a way to find a cure for his illness, Nine told his teammates that he plans to join the League of Villains to undergo an experiment by Dr. Kyudai Garaki, better known as Dr. Daruma Ujiko.

Dr. Garaki conducted an interview to find out why he wants to undergo his experiment, and after hearing Nine's explanations, and concluded that he's definitely a perfect candidate, noting that his mind and body are in the right condition. The operation consists of granting him a copy of the All For One's own Quirk, although this is something that Nine ignored. Despite not knowing what the experiment would do to him, he felt like everything will turn out fine. As Nine was sealed up for the experiment, he noted that he will create an ideal world not only for himself but for his teammates as well.

My Hero Academia: Heroes: Rising
After several months of operation, Dr. Garaki manages to adapt the All For One factor to Nine's body. With the operation completed successfully, Garaki requests the League of Villains to transport Nine in an armored truck to a specific point. When they ask what it is, the Doctor simply tells them that it is something that has nothing to do with them. Although they do not like to be treated as simple delivery men, Tomura Shigaraki agrees to his request.

Somehow, the information of that delivery is leaked, presumably by Nine's crew, and the heroes set up an ambush on the mountain road they are going to pass. A fast-paced chase ensues when the heroes try to stop them. Despite the opposition shown by the members of the League, the truck ends up crashing. However, when the heroes investigate the crashed vehicle, Nine had already escaped from the scene, reuniting with his allies at a hidden location in the forest nearby.

Nine tells them that the operation was a success, obtaining great power but also worsening the symptoms of his illness. Chimera considered that the operation was for nothing then, but Nine corrects him saying that it is not true, because with his new power, he only needs to steal a Quirk to help him to overcome his illness, and in this way, he will be able to build the utopia that they had always dreamed of.

One day, they end up attacking a civilian, Mr. Shimano, who is on a business trip in Kyushu. He is attacked by Nine and his screw, with Nine using his Scanning Quirk to scan him and proclaims that he has found what he was looking for. He then uses his All For One Quirk to steal and absorb Mr. Shimano's Cell Activation Quirk.

When Nine takes Mr. Shimano's power, he uses his original Quirk, Weather Manipulation, to call lightning down to destroy parts of the city. Nine and their groups are excited that they can finally put their plan into action to fulfill their dreams. Nine then freezes up in pain as his cells begin to degenerate, and he realizes that Mr. Shimano's Quirk isn't compatible with him because it only works on A-Type blood and he has B-Type.

Chimera laments over the team's struggle to cure Nine, but Slice shows them the video recording of Mr. Shimano’s children, Katsuma Shimano, and Mahoro Shimano. Nine remembers that Quirks are hereditary and decides to aim for the kids as one of them may have a Quirk that is similar to their father's but also compatible with his blood-type and body.

They hijack a ferry to travel to Nabu Island, crashing the ship they used into the harbor once they arrive. They also destroy all of the boats to prevent anyone from escaping. Nine orders his teammates to cause much destruction as possible in order to isolate the island from the outside as well as divert attention from their true goal while he hunts down the siblings. What neither of them didn't count is that all the students from Class 1-A of the U.A. High School are on the island for the Hero Work Recommendation Project. When they notice the attacks, the students confront the villains. Mummy is defeated and captured.

Nine finds the children, and using his Scanning Quirk discovers that Katsuma has the Quirk he was looking for. Nine is about to steal the boy’s power when Izuku Midoriya appears to protect them and fight him. Nine easily overwhelms Izuku, and even he tries to steal One For All from him, but something prevents it. Nine comments that he was unable to steal it, saying that rather it didn't fit in the slot. Due to this, he correctly assumes that the Quirk's existence is a miracle in it of itself and decides to dispose of Izuku, using his Air Wall Quirk to deliver a powerful blow to him, pushing the kid back and stunning him. Izuku tries to get up to defend the kids, who haven't run away, but Nine blasts him with his Bullet Laser Quirk, which easily penetrates the boy's flesh and immobilizes him.

Then, again, before Nine can steal Katsuma's Quirk, Katsuki then appears to face Nine, and together with Izuku, they fight the villain. The determination of both students forces Nine to use his Weather Manipulation Quirk to summon a powerful blast of lightning from the sky, defeating Izuku and Katsuki and presumably killing them. However, again, before he can take the boy's Quirk his illness sets it and causes him to freeze and hurl in pain. Slice arrives to take Nine away and signal to her fellow villains to retreat after the Shimano siblings, as well as Izuku and Katsuk, are rescued by some of the other Class 1-A students.

The next morning, after recovering from his illness in a lighthouse, Nine is determined to take Katsuma no matter the cost. Slice informs him that the students of the U.A. have sheltered all the inhabitants of Nabu in the vast underground caves under the ruins of Mount Shiroyama. He and his allies make their way to Mount Shiroyama, where the students were waiting for them. During the previous night, after recovering from his intense injury through Katsuma's own Cell Activation Quirk, Izuku and his companions had devised a plan to deal with the villains and particularly defeat Nine by taking advantage of his illness, planning to ultimately make Nine wear himself out by using his Quirks too much.

When the students see the villains are close enough, they put their plan into action. Yuga Aoyama and Momo Yaoyorozu start attacking them from afar with their respective Quirks at full power. While Nine blocks the attack with his Air Wall Quirk, Slice and Chimera break away from Nine in their own separate directions to avoid the blast, unaware that they are falling right into the student's trap.

With their attack, Class 1-A students manage to separate Nine from his allies. Then the students take turns attacking him as they had planned. Despite their attempts to stop him, Nine gradually defeats the students until it’s Izuku and Katsuki's turn to face him. After a tough fight, they finally get Nine to his limit and the backlash of overusing his Quirks kicks in.

In his despair, the villain takes a heavy dose of a quirk empowering drug and goes beyond his limit, using his Weather Manipulation Quirk to summon a massive lightning strike, striking Izuku and Katsuki. The rest of the students try to apprehend Nine, but the villain easily defeats them and catches up to Katsuma and Mahoro who were being carried away by Mezo Shoji. He holds Mahoro hostage after she runs at him to protect her brother and threatens to kill her if Katsuma doesn't surrender his Quirk to him. Katsuma runs towards Nine to save her, but before he could reach the villain Nine is hit by Izuku Midoriya, making Nine drop Mahoro who was caught by Katsuki Bakugo. When Nine asked how they survived his lighting, Katsuki says that they used Denki Kaminari as a lightning rod to absorb the hit.

Izuku and Katsuki begin to defeat Nine, taking advantage of Nine's illness which was currently making his Quirks significantly weaker as well as himself. On the verge of defeat, Nine uses the entire healing and empowering drug in his life-support system which amplifies his Quirks, most notably the Weather Manipulation Quirk, to the maximum. He then takes full advantage of the opportunity to create an immensely powerful storm above the island, additionally making various tornadoes and lightning strikes which begin destroying absolutely everything on the island. Most notably the ground can be seen flying into the air due to the intensity of the storm.

With Nine's power so incredibly boosted, Izuku and Katsuki's attacks do absolutely nothing to him, even able to withstand Izuku's One For All: Full Cowl - 100% and Katsuki's Howitzer Impact without issue. Nine then proceeds to pummel them with his Bullet Laser Quirk, then using his Hydra Quirk to restrain and crush them in the air. While the two student's were restrained in the air, Nine tells them about his dream and views of how a super human society should truly be, but Katsuki comments that it would never work. Izuku, while being crushed, realizes that the only way to win and save the world from Nine was to share the power of One For All with Katsuki, thinking that it was All Might, and a true hero, would do. Izuku then transfers One for All to Katsuki and the two break free from Nine's Hydra Quirk, standing tall and activating their respective One For All: Full Cowl - 100%. Izuku and Katsuki then do a double Detroit Smash to destroy the massive storm that was above the island and proceed to use their combined power to defeat Nine once and for all.

Miraculously, after everything, Nine managed to survive that attack, being blasted away to a field surrounded by nice flowers. However, by using a Warping Quirk, Tomura Shigaraki appears in front of the beaten Nine to confront him. Nine says determinedly that he would create the world he needed to create. When Tomura says that he will fulfill Nine's dream, Nine says that there can only be one true king. Tomura agrees, putting his hand on Nine's face and saying, "That's right, just one," before killing Nine with his Decay Quirk and leaving the island.