Delta

is an "Inner" from the organisation Kara.

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 obsesses about her appearance.

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.

Aside from her destructive nature, Delta is incredibly cold-hearted and sadistic, attempting to kill Himawari Uzumaki simply to psychologically destroy Naruto, while also showing no remorse on trying to kill an innocent girl, while 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.

Appearance
Delta has long, curly, blonde hair and light-brown eyes, with vertical lines running through her pupils and irides. She has a green tattoo of the Roman numeral "Ⅰ" in the centre of her forehead and wears a black and red cloak and 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. She also wears yellow lipstick and matching nail polish on her fingernails.

Abilities
Being an Inner of Kara, Delta is regarded as a complete monster with regards to her abilities, evident by being capable of holding her own against the Seventh Hokage, who is regarded to be the strongest shinobi in history.

Body Modifications
Delta's body has been extensively enhanced by highly-advanced Shinobi-ware to the point where she had become a full cyborg, capable of body transformations similar to Kawaki's. On her back, she keeps a drone for spying purposes, which can go through normal chakra barriers around villages undetected since it doesn't use chakra and to 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, (albeit she apparently has difficulty absorbing more complex techniques like the Sage Art: Lava Release Rasenshuriken) or alternatively launch powerfully destructive beams cable 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 hold her own against the Seventh Hokage despite him being in Six Paths Sage Mode. The two ended up fairly even during their exchange with Delta landing several strong hits on her opponent. When combined with her Shinobi-Ware, she forced Naruto to keep his guard up during their fight.

Ao Arc
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.

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 a angrily 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 the village's sensory division, 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 begins 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 manages to dodge the lethal beams, the split-attention let Delta begin landing more solid blows. Fearing for his dad's safety, Boruto recklessly launched his Vanishing Rasengan on the foe, who quickly absorbed the attack to reenergize 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.

Trivia

 * "Delta" is the fourth letter of the Greek alphabet.