Personality
Nui has a childlike, jovial, and happy-go-lucky demeanor; always smiling, and acting very friendly and even polite with everyone, demonstrating excessive intimacy towards even Satsuki and revealing to Ryūko in a rather nonchalant way the fact that she killed her father. According to Ragyō, Nui is a free spirit and will do whatever she wants according to her whims. Her often bubbly behavior and nonchalance towards anyone that stands in her way often puts her at odds with the main cast, and can easily become bored while she playfully seeks violence to a sadistic degree.
When she finds herself injured or outmatched, she becomes more frantic, obstreperous, and aggressive, dropping all manner of her cheerful demeanor, which becomes more evident by the endgame after Ryūko cut off her arms. Nui is also known for holding heavy grudges, like Isshin for cutting her eye out and Ryūko for cutting both her arms.
Powers
Life Fibers
* Superhuman Physical Prowess - As a Life Fibers-infused human, Nui possesses immense physical strength, speed, reflexes, durability and endurance. She is able to handle herself exceptionally well in battle, being able to effortlessly fight against the Four Devas, who were all wearing enhanced, Three Star Goku Uniforms, fight on even grounds against Kamui-wielding fighters such as Satsuki and Ryūko and easily defeat the Nudist Beach forces. In spite of her natural strength, due to the particular nature of the Life Fibers infused to her, Nui is unable to don a Kamui, as it would have no effect on her.
* Regeneration - As a Life Fibers/human hybrid, Nui can regenerate from any wounds and even lost limbs almost instantly, regardless of their severity. The only exception to this healing power is if Nui entire limb is cut with either the Scissor Blades or two weapons forged from Bazukan, as they nullify Life Fiber restoration.
* Mon-Mignon Prêt-à-Porter - One of Nui's unique skills allows her to create replicas of herself that can either fight her opponents or act as distractions. Although physically identical to Nui and possessing all of her abilities, the duplicates appear to be far less powerful than the original, relying mainly on their superior numbers.
* Mental Refitting - Much like Ragyō, Nui can release Life Fibers from her hands that ensnare opponents and turn them into mindless puppets.
* Shapeshifting Arms - For the final battle, Ragyō replaced Nui's lost arms with Life Fiber replicas that can alter their shape. During the final episode, Nui's new arms transformed into blades for melee combat and bat-like wings for flight.
Natural Abilities
* Infiltration and Disguise Skills - Nui also appears to be extremely skilled when it comes to mimicry and infiltration. She was able to completely disguise herself as Shinjirō Nagita, disguising her height, hair style, gender and voice almost perfectly. She was also somehow able to create fake student data for Nagita, which appeared genuine upon inspection but disappeared immediately when she discarded her disguise. The only clue to her true identity that she apparently could not change was her eyepatch, which she instead covered up. In order to support her disguise she also used lifelike puppets to imitate the One-Star students chasing Nagita, indicating that she is also skilled at puppetry and ventriloquism.
* Piloting Skills - Nui is also a skilled pilot, as seen when she hijacked Satsuki's personal helicopter and flew it back to the Kiryūin manor
* Master Sewing Skills - Being a Life Fibers/human hybrid and the Grand Couturier, Nui has a deep knowledge of how Life Fibers clothing is made, as demonstrated when she effortlessly spotted and removed Sanageyama's uniform's Banshi, dismantling the uniform. Likewise, she altered the Kamui Junketsu to be worn by Ryūko by sewing the Kamui's Life Fibers to Ryūko's own in order for the Kamui to possess her, making it extremely difficult for it to be removed from her body. She can sew high quality garments, especially Life Fiber based with ease, even after losing her arms as seen by her completion of the Shinra Koketsu.
* Fingernail Hooks - The bottom edge of Nui's fingernails are lined with small hooks that can catch threads. She can use these hooks to grab and remove Banshis from uniforms.
Others
It is also of interest to note that of the characters shown in the series thus far, she is the only one to be capable of performing reality-warping fourth wall breaking feats such as leaning upon the characteristic large red text which forms her name, and completely disregarding the space separating her from Satsuki, allowing her to run her fingers through her hair as though they were standing eye to eye, when in reality, they were many meters apart. This is most likely for artistic effect for her character and not an actual ability.
Former Abilities
* Scissor Blade (片太刀鋏 Katatachi Basami) – Nui's signature weapon is one half of a giant pair of scissors, which she took from Isshin Matoi after defeating him. She wields the scissor as her main weapon, as one-handed, single-edged sword. The blade is capable of cutting Life Fibers, which are otherwise indestructible. Her skill with the blade is equal, if not superior to that of Ryūko's own.
Scythe Mode - Like Ryūko's blade, Nui can alter the shape of her Scissor Blade. During the battle on the S.S. Naked Sun, she converted her blade into a large, double-sided scythe. Apparently, this form can also increase the blade's power, as Nui intended to use it to sink the ship.
Razor Tape Measure - Nui used a measuring tape with retractable blades during her attack on Isshin Matoi's lab. It was destroyed by the Scissor Blades.
