Naoya Zenin

Naoya Zenin is an antagonist in the Jujutsu Kaisen series. He is one of the sons of Naobito Zenin and believes himself to be the true heir of the Zenin Family. Naoya is also the head of the clan's elite unit of jujutsu sorcerers, the Hei. He serves as the primary antagonist of the Itadori's Extermination Arc.

Appearance
Naoya is a young man with small sharp eyes and light-colored hair accented with dark tips. He believes himself to have an appearance befitting a Family Head unlike Jinichi Zenin. He wears two earrings on the top of his left ear and sports formal attire. He wears a dark-colored kimono over a white high-necked shirt with a buttoned collar and completes his outfit with light-colored hakama bottoms.

Personality
Naoya embodies all the stigma about the Zenin family. He cares little for those he considers weak and believes women are only to serve as wives. Naoya claims all his elder brothers are losers and cares little for Maki due to her "inappropriate" attitude as a woman.

Even those considered to be his kin are not above Naoya's own personal gain. The news of his father's death came as a delight to Naoya. He's arrogant and believes only he should be the next head of the family, leading him to clash heads with Ogi and Jinichi due his disrespectful nature.

Megumi Fushiguro who is Naoya's relative, is simply another obstacle to him. Naoya is willing to kill Megumi and use his political influence to become head of the Zenin Family no matter what.

Itadori's Extermination Arc
After the Shibuya Incident, Naoya was called to stay by Naobito's side along with Ogi Zenin and Jinichi Zenin. On the way there, he made misogynistic comments towards Maki and Mai, claiming that Maki does not deserve to live and Mai is much more acceptable for the Zenin clan.

When Naoya met Ogi and Jinichi, he stated that he would become the new clan leader, insulting his brothers and Jinichi in the process. After a short scuffle, Furudate walks out of Naobito's room and announces the clan leader's passing. The short man then read Naobito's will, revealing that, in the case of Satoru Gojo's disappearance, Megumi Fushiguro is to become the next clan leader. This fact angers Naoya, which is enough for him to head to Shibuya and attempt to hunt both Sukuna's vessel and Megumi down, killing two birds with one stone.

He arrives shortly after, finding Yuji with Choso as they were exorcising curses. Naoya is initially disappointed that Megumi is not there, but he quickly attacks both Yuji and Choso. However, the fight is interrupted by the arrival of Yuta Okkotsu. Naoya notices his immense presence, immediately presenting himself as an ally and asking Yuta not to tell anyone else that he was here.

Naoya makes use of the situation and attacks Choso as Yuta chases after Yuji. During the initial scuffle, he comments that he knows about Blood Manipulation and Choso has no way of winning. The fight is taken into an underground passage, where Naoya seemingly overpowers Choso. The curse-human attempts to use Flowing Red Scale: Stack to turn the tables, but the Zenin family member manages to counter by stabbing Choso and hoping he bleeds out. After that sneak attack, Naoya makes an off-handed comment about his brothers which prompts Choso to talk about the value of brotherly bonds.

Choso then makes use of the fact he's half-curse and launches his blood towards Naoya in a giant wave. The Zenin family member attempts to dodge, but some blood eventually gets on his clothes and Choso then defeats him with Supernova, managing to poison him with his blood in the process. Before Choso could finish his opponent off, Yuta arrives and knocks the curse-human out. Okkotsu, who carries Yuji's unconscious body behind him, then comments that Naoya looks hurt.

Naoya feels insulted by Yuta staring down at him, but a sudden pain causes him to vomit. The Zenin family member is bewildered, not understanding right away why his body reacted this way. As he understands that Choso must not have been human, Yuta offers to heal him in exchange for informing the higher-ups of Itadori's death. Naoya presumably accepted the deal and left Shibuya.

Culling Game Arc
When Maki arrives at the Zenin household, Naoya immediately insults Maki about her burnt face. Maki counters this by saying that she thought Naoya judged women by their butts instead of the face. Naoya ignores her and tells her to answer his question. He adds on that Maki is unable to use cursed techniques, nor see cursed spirits. He also says that her face was all she had before it was ruined, Naoya adds that he's been lonely lately asks Maki if he should bully her like he used to in the past. Maki ignores this as Naoya asks her if she's going to follow Megumi Fushiguro and Yuta Okkotsu like a lap dog.

Now in a different room, Naoya talks to Jinichi as he says he's too reckless and that Megumi is the better choice. While the two are chatting, the alarm sounds as Naoya wonders why there's so much noise. Ranta who suddenly rushes in informs the two that Maki has gone mad and also has killed Ogi. He adds on that the Kukuru unit has also been deployed to go after Maki. Naoya thinks to himself is surprised that Maki managed to kill Ogi.

After both the Kukuru and Hei units are slaughtered by Maki, Naoya arrives and confronts her after she throws Jinichi's head into the water, asking if she has a human heart. Maki responds by saying she no longer has a heart as it was taken from her.

Abilities and Powers
Overall Skill: Naoya has yet to showcase his full power, but he is a special grade 1 sorcerer who believes he is far stronger than his fellow clan members.

Immense Speed And Reflexes: Naoya is capable of moving super fast, shown being capable of blitzing Choso and Yuji Itadori, traveling so fast that it makes it seem like he teleported. Naoya has also displayed excellent and blinding reflexes, being able to evade multiple attacks while being able to process his surroundings just as quickly.

His prowess in movement speed also enables him to single-handedly take on 2 expert combatants simultaneously, evading attacks and dealing swift blows effortlessly. Although it hasn’t been revealed how he is able to move at such high speeds and what limits there are to this ability, Choso suspects that this is due to a cursed technique.

Naoya also seems to be able increase his speed even more, as he states “Shall I try upping my speed?” which also implies he was far from moving at top speed, judging by his casualness when saying those words.