Nomu appears to be a large, black humanoid monster with a very muscular body that has many scars on it. His brain is exposed on the top of his head, while his large eyes are around it. His mouth is in the shape of a bird's beak that has sharp teeth in it.
Before his transformation, Nomu had the appearance of a regular human with light olive green hair and thick lips.
Due to the intensive body experimentation done to him, Nomu is not able to speak nor can he think for himself. To compensate for this, he is only capable of following orders and will do so without question, as shown when he follows Tomura's orders. He is very brutal with his enemies and will not show any mercy.
Nomu was once a small-time thug. Under unknown circumstances, Nomu's body was experimented on through DNA injection from four different people, causing Nomu to acquire Quirks in the process, eventually resulting in Nomu becoming an artificial human.
Nomu appears at the Unforeseen Simulation Joint after Kurogiri warps him and the other villains there. When Shota knocks Tomura Shigaraki down onto the ground, Nomu appears before Shota and fights him, defeating him with ease.
When Shota uses his Quirk to save Tsuyu Asui from Tomura, Nomu smashes Shota's head into the ground. He then blocks Izuku's One For All empowered punch, not even receiving a single scratch from it.
All Might attacks Nomu with Carolina Smash, but does little damage to him. Nomu tries to counter, but All Might dodges. All Might then uses a backdrop slam against Nomu, but Kurogiri opens a gate with his Quirk, allowing Nomu to evade the attack and then clutch onto All Might. However, half of Nomu's body is frozen by Shoto Todoroki, giving All Might the opportunity to escape from Nomu.
After Tomura orders him to get rid of Katsuki Bakugo and retrieve Kurogiri, Nomu gets out of Kurogiri's gate, but his frozen half is then shattered. After getting out, Nomu begins to regenerate, regaining his lost limbs. He then attacks Katsuki, but his punch is blocked by All Might who is sent back a distance by Nomu's punch.
However, Nomu's attack forced Katsuki to evade, allowing Kurogiri to escape from Katsuki. Nomu and All Might engage in a fist fight, punching each other blow for blow (although Nomu has the upper hand thanks to his Quirk). All Might decides to go beyond his 100%, and, with a devastating punch, Nomu is sent flying out of the U.S.J, defeated.
All Might's punch sends Nomu flying into a forest 400m away from the U.S.J and he is captured by the authorities, putting up no resistance whatsoever.
Nomu has been imprisoned by the Police Force, locked up in a straitjacket. The Police Force try to get information from Nomu, but he does not respond or react to anything they do. Instead, the Police Force did a DNA analysis on Nomu.
Overall Abilities: Nomu has shown to be very powerful and one of the strongest artificial human seen thus far, being able to defeat Shota Aizawa (a formidable pro hero) with no difficulty and severely injure All Might to the point where he couldn't move. Designed as a counter to All Might, he has been described as a "humanoid punching bag" for his combination of Quirks that allows him to take powerful blows and debilitating injuries without a thought.
Immense Strength: Nomu possesses an incredible amount of raw physical strength, being able to fight on par with All Might for a considerable amount of time.
Immense Speed: Despite his herculean bulk, Nomu is blindingly fast. He is able to intercept Izuku Midoriya's full power Smash blow and able to keep up with All Might in a pummel contest.