Delta

is an Inner from the organisation Kara.

Background
In the anime, Delta was searching for children in a village for Kara to use as candidates as Jigen's vessel when she came across Kawaki's blood soaked cloth after the young latter was bullied by other children. Afterwards, Jigen would later buy him off from his father.

Personality
Delta has a short temper, which makes her destructive at times, such as kicking a table that her leader was eating at to vent her frustrations. She is very focused on missions, getting visibly irritated when they are not completed within the expected time frame. Jigen mentioned that she has been worried about her weight previously, which might indicate that she cares about her appearance. She is very open about her views of others, basically hating all the Inners from Kara, apart from perhaps Jigen.

She also appears to be quite impatient, growing increasingly agitated when Koji was taking too long while looking for Kawaki in Konohagakure. She's also very confident of her abilities, openly confronting Kawaki while in the company of the Seventh Hokage and being unfazed while standing face-to-face with the legendary world hero. Delta is also quite perceptive, seeing through Naruto's attempts to have her reveal her plans by hiding his power and pretending to be defeated. She also apparently has a strong superiority-complex, quickly viewing the Seventh Hokage as beneath her and likewise became fixated on killing him after he defeated her.

Aside from her destructive nature, Delta is incredibly cold-hearted and sadistic, attempting to kill Himawari Uzumaki simply to force Naruto into her Destruction Beam's track, with no remorse displayed in trying to kill an innocent girl, seemingly enjoying the thought of it. On the contrary, she was shocked and furious when Kawaki blocked the hit at the cost of his own arm, never expecting he would sacrifice himself in such a manner. As with Jigen, she saw Kawaki as no more than the "Vessel" for Kara, in which she openly treated him as an object as opposed to a person with free will, hence her anger at him for using his own body as a shield.

Appearance
Delta has long, curly, blonde hair and light purple eyes with yellow eye-shadow, with vertical lines running through her pupils and irides. She has a green tattoo (black in the anime) of the Roman numeral "I" in the centre of her forehead and wears yellow lipstick and matching nail polish on her fingernails and toe nails. She wears a black cloak with a pink inner colour, a turquoise outfit with an exposed heart shape cut-out on her back, triangle shape cut-out bishop sleeves, a triangle shape cut-out on her chest, white wrist cuffs, red triangle earrings, with black and red striped tights, and long white high-heeled shinobi sandals. In the manga, Delta's outfit was embroidered with pink studs on the centre.

Abilities
Being an Inner of Kara, Delta is regarded as holding completely monstrous abilities, evident by her mere presence terrifying Kawaki to the point of sweating and being capable of standing up against the Seventh Hokage, who is well-regarded to be the strongest shinobi in history, although Naruto was not fighting at full power to capture her alive. She can also use the Yin Release to perform the Genjutsu Communication.

Body Modifications
Delta's body has been extensively enhanced by Amado with highly-advanced Shinobi-ware to the point where she had become a full cyborg, capable of body transformations similar to Kawaki's. Even more, her very consciousness can be uploaded into replica bodies. On her back, she keeps a drone. It records her consciousness should she be destroyed, it cannot be detected by chakra sensing as it doesn't use chakra, allowing it to spy more effectively, and it can track invisible targets. She can modify her legs for high-speed travel, creating practical rocket legs similar to those used by the Asura Path. Her eyes can absorb and release ninjutsu, as she did with Naruto's Rasengan or alternatively, launch a powerful capable of overpowering the strongest of regenerative abilities. She could also create several wood-like protrusions from her legs that are strong enough to pierce even the defences of Naruto's Six Paths Sage Mode shroud. Her modifications grant her tremendous raw strength, able to casually grind her fingers through the trunk of a sturdy tree and make Naruto bleed with a single punch. She has also displayed the ability to shroud herself with chakra to increase her physical abilities.

Taijutsu
Delta has shown herself extremely skilled with taijutsu, able to contend against the Seventh Hokage despite him being in Six Paths Sage Mode, landing several strong hits on her opponent and able to force Naruto to keep his guard up and pressure him when combined with her Shinobi-Ware.

Kara Actuation Arc
In the anime, Delta was present when Jigen called a meeting with the Inners, informing them of the destruction of one their facilities in Amegakure set by an Outer.

Ao Arc
In the anime, as Delta was testing out the latest modifications to her body, she grew annoyed at how her legs didn't seem to react as fast as she wanted. She called Amado for assistance, believing he slacked off on the work. Later, she joined Amado in overseeing the transport of the "Vessel" in Victor's stealth ship, sceptic of his helpfulness.

Delta attended a meeting held by Jigen to discuss the urgent situation relating to the missing "Vessel". As Jigen dispelled the genjutsu, he voiced that they must recover the vessel at all costs. In the anime, she was called by Amado alongside the other Inners to have their bodies checked to detect anything suspicious regarding the traitor under the pretense of just being a maintenance. She was also shocked to learn from Amado that Victor was killed by Koji. Delta would later taunt Code about Koji Kashin being on Jigen's good side, as well as Code's own need to impress him.

Later, as Delta prepared to test the maintenance work on her body, she was attacked by Code. He had decided to uncover the traitor himself, starting his interrogation with Delta since her number was "I". As he accused her, Delta countered that Code seemed the most pleased at the vessel's disappearance. Code was furious and primed to attack, only for Amado to arrive to calm things down. He revealed that the system check on everyone revealed no signs of treachery. Delta however pointed out that Amado could have been using the situation to hide his own treachery. While Amado insisted he had nothing to gain from clearing the innocence of others if he really is the traitor, Delta remained wary of him. Delta would later sneak in to check on the files on Code and considered Koji Kashin a traitor.

Kawaki Arc
During dinner with Jigen, Delta was concerned about Koji Kashin trying to retrieve Kawaki. After listening to Jigen's reasoning, she angrily kicked away the table and demanded to know the leader's explanation for how long the vessel's recovery was taking. Delta later received permission from Jigen to check on the mission's progress herself, and report back to him if there are any issues.

She joined Koji from afar and was asked by him if she brought an Outer which she confirmed that she brought Garō to retrieve Kawaki. She watched as the defiant Kawaki attacked Garō. Delta was also surprised to find out Boruto Uzumaki has a possession of Kāma. After Kawaki killed Garō and fainted from overheating, Delta felt it would be a good time to get rid of the Konoha-nin and retrieve Kawaki. Koji argued that Boruto having a Kāma warranted further observation before taking action, and that with the blimp crash, it was inevitable that the world would learn of Kara's existence. Later, she and Koji arrived at the main gates of Konohagakure to retrieve Kawaki.

Delta stated that it would be difficult infiltrating, but despite her statement, she was told to stay put by Koji, who entered the village without setting the barrier off. Much to her dismay, she believed that Koji tricked her so he could continue the mission without her surveillance. Growing impatient with Koji not returning and being in an angry mood to kill someone, she launched a drone from her back as it could bypass Konoha's barrier without being detected, and requested it to locate and inform her of Kawaki's whereabouts before it flew off. When it found him training with Boruto, she entered the village's airspace, during which her presence became known to Ino and the Konoha Barrier Team, and launched herself towards his location using her transformed legs. Approaching the vessel, she encountered the Seventh Hokage and his two children beside him.

Delta boldly demanded Kawaki to be handed over. Kawaki confirmed her identity as an Inner from Kara to Naruto. Naruto gave instructions to Boruto and Kawaki before fighting Delta. Naruto initially outperformed her in taijutsu, but Delta began using her shinobi-ware to launch sneak attacks and absorb Naruto's Rasengan. The battle escalated as Naruto entered his Six Paths Sage Mode, but Delta was able to pin him down. Naruto tried to discern Delta's objectives, but Delta was able to see through his ruse, noticing he was already healing, and considering him to be a monster much like herself. She activated a chakra cloak of her own before continuing to fight Naruto, using his own absorbed Rasengan against him.

As Naruto began to gradually wear down his foe, realising that she couldn't beat the Hokage at this rate, Delta unleashed her ace, a destructive eye-beam that would override even the strongest of regenerative powers. While Naruto managed to dodge the lethal beams, the split-attention let Delta begin landing more solid blows. Fearing for his father's safety, Boruto recklessly launched his Vanishing Rasengan on the foe, who quickly absorbed the attack to reenergise herself. Going for a new tactic, Delta then launched her beam at Himawari, knowing that she would inevitably hit someone, whether it be her target or the Hokage acting as a human shield for his daughter. To everyone's surprise however, it was Kawaki who blocked the blast, at the cost of his right arm. Regardless, this turn of events greatly angered Delta even more.

Delta scolded Kawaki for damaging his body, which as the "Vessel", she considered to belong to Kara and Jigen. She believed Amado capable of healing the damage. As an enraged Naruto continues the fight with Delta, the two exchange blows until Delta hits the ground. As he approached, Delta attempted to finish him with her eye beams point-blank, but he dispersed it with a Big Ball Rasengan. Delta absorbed it, and Naruto made a bigger Rasengan, to the point her eye could no longer absorb chakra, causing it to fail and losing the connection with her drone. She attempted a physical attack, but Naruto dodged her and landed his Super-Ultra-Big Ball Rasengan on her, leaving her on the bottom of a large crater.

As her last defence, her body self-destructed, making her enemies retreat from the blast. However, her still intact drone retreated to a Kara base, where it connected to a terminal and activated a spare body. Furious at her defeat, she vowed to get revenge on Naruto, only to be teased by fellow Inners and for Jigen to silence the discussion. She reported that Koji decided to let events play out to gather more information, and that Boruto had a genuine Kāma of his own.

In the anime, as Jigen was recovering from overtaxing himself against Naruto and Sasuke, Delta went to check on Boro in the other dimension as they lost contact with him. There, she found that he had been killed and that the Hokage had escaped. She soon reported to Jigen. She was then tasked with destroying Boro's cult base, ensuring that no one could gain access to his Space-Time Gate. Upon reaching the base, she without hesitation began incinerating all in her sight. Upon completing her mission, very few followers of the cult remained.

Later, after Jigen defeated Naruto Uzumaki and Sasuke Uchiha in battle, sealing the former away, he returned to Kara's headquarters with his body breaking down. Delta watched on as Jigen was hooked up by Amado to treat his body. She watched as the two discussed the situation, and insulted Amado when he looked at her. She discovered Koji and Amado attempting to leave without Jigen's permission and tried to stop them, but was knocked out by a shut down command issued by Amado.

Later, according to Amado, Code was the only surviving Inner of Kara left, implying that the shut down command issue he had given to stop Delta was permanent or that only he could disable it.

Trivia

 * Delta is the fourth letter of the Greek alphabet.