Nanashi Uchiha

, formerly known as was a kunoichi of the Uchiha clan during the Warring States Period. Because of her extraordinary abilities, Nanashi was treated as nothing more than a weapon by her own clan and was always locked away in a cell, only being called out for battle. She was ultimately sealed away by the combined efforts of the Senju and Sarutobi clans. She was released almost a century later by Merz to be used as his tool for war, using Nanashi's hatred of shinobi and the world alike to gain her trust.

Background
Nanashi was born as "Hikari Uchiha" by her parents, who wished her to live her life in the sunshine as much as possible, hence her birthname. However, her parents were killed at some point during the vicious war-torn Warring States Period, leaving her orphaned. Once her fellow Uchiha clan members discovered Nanashi's powerful abilities, they decided to use her as a weapon for battle, telling her only purpose was to serve them in battle, and gave her the name "Nanashi" to signify her lack of identity as a human being. For several years, Nanashi was kept locked away by her own clansmen, being treated as a weapon, often being referred only as "it" by others. Ultimately, however, during a battle against the Senju clan, Nanashi's power forced them to retreat, only for them to return with assistance from the Sarutobi clan, who managed to defeat the Uchiha and seal Nanashi away in a scroll, preventing her from being used again for battle.

Personality
Because of the extreme mistreatment she suffered at the hands of her own clan, being treated as nothing more than a weapon, not even being referred to as a human being, but only as an object, Nanashi developed a deep hate for not only her own clan, but shinobi as a whole, along with reality itself. As a result, Nanashi eagerly accepted Merz's offer to bring chaos to the world in order to gain her revenge upon shinobi. However, upon meeting Boruto Uzumaki in the virtual game world she created, Nanashi began having conflicting feelings; while initially annoyed with Boruto's persistence to talk to her and impress her, she gradually found him interesting and different from others, who only talked to her as part of her duties as a "guide" for the game, whereas Boruto genuinely wished to become her friend.

At the same time, however, Nanashi still struggled to let go of her hatred, and began suffering from great emotional turmoil over her feelings of hate against her feelings of joy regarding Boruto, but still went ahead with her plans, although she unknowingly caused herself great harm as she subconsciously wished to keep Boruto safe from her own plans. When clashing against Boruto, Nanashi was unable to bring herself to kill him, shedding tears and pleading for Boruto to stay away, but due to Boruto's unwavering determination to rescue her from her hatred, she ultimately came to accept his feelings and granted him her chakra to help defeat Merz, although at the cost of her own life. After Boruto traveled back in time to the Warring States Period with the help of Toneri Ōtsutsuki, Nanashi was once again saved by Boruto, this time from her own clan, and after seeing just how Boruto was determined to save her, and hearing his words about choosing her own path instead of accepting one made from others, she decided to live the rest of her life unaligned with any clan, and with her birthname returned to her by Boruto, she lived a modest life surrounded by people who cherished her, and while refusing to speak about her tragic past, Nanashi would only, and happily, talk about meeting Boruto and how her life was influenced by him, leaving an anecdote behind, thanking him for changing her life for the better.

Abilities
Nanashi was considered immensely powerful by her own clan, to the point that she was wielded by the Uchiha as a tool for war during the Warring States Period. The Sarutobi and Senju clans, not formerly allied at this point, banded together for the sake of utilising a fūinjutsu to seal Nanashi away. While confronting Boruto, Mitsuki, and Sarada in Naruto Heroes, she overwhelmed them with her strength; despite the three each being some level of prodigal, Mitsuki noted Nanashi was stronger than all three of them. Nanashi possesses enough chakra reserves that, when her power is fully unleashed, it manifests as visibly.

Nature Transformation
Nanashi possessed the natural Uchiha disposition for the Fire Release chakra nature. Born and raised in the Warring States Era, Nanashi was able to use complex Nature Transformation at a young age, including the Uchiha's rite of passage technique - the Fire Release: Great Fireball Technique. Her skill in Fire Release allowed her to also utilise the Fire Release: Great Dragon Fire Technique, and its subsequent technique, the Fire Release: Dragon Flame Release Song Technique. Nanashi was even capable of Fire Release: Great Fire Annihilation, the pinnacle of the Uchiha clan's Nature Transformation, showcasing her skill born through war.

Sharingan
In spite of appearing young, Nanashi possessed a fully matured Sharingan. It was unknown when she awakened it, but with these eyes, she possessed the same heightened perception as other members of the Uchiha clan. She has immense skill in Genjutsu, able to manipulate the Genjutsu world of Ninja Heroes easily, comparing herself to a "wizard" in the space of her Genjutsu.

Mangekyō Sharingan
Alongside her Sharingan, Nanashi was in possession of a powerful Mangekyō Sharingan, a feat at this point in time associated solely with Madara Uchiha and his brother, Izuna. She had the abilities Tsukuyomi and Amaterasu implanted into her eyes, and was able to utilise the Engraved Tsukuyomi through her Mangekyō Sharingan as well. While she is skilled in the use of Amaterasu, the strain of the technique takes its toll on her eyes. Furthermore, Nanashi shows the capability to manipulate the shape of the black flames, such as taking a swirling vortex to protect Boruto. Additionally, she had a powerful unique Genjutsu, the Yachihoko. This Genjutsu allowed Nanashi to control others by erasing their memories and implanting powerful orders in their minds. Additionally, it gave her full access to their chakra, allowing her to transport it as needed.

Plot Overview
Nanashi remained sealed away for the duration of the Warring States Period, and throughout each of the Shinobi World Wars, well into the modern era, where she was unsealed by Merz and Teguse, of Zero. Manipulating Nanashi's hatred for the shinobi world, he promised revenge by plunging the world into anarchy. Nanashi, who was already immersed in hatred, accepted his offer and began to work with Zero.

Initially appearing as a guide character in the game "Ninja Heroes", Nanashi met Boruto Uzumaki. Initially, they did not get along, as Nanashi found Boruto's energy to be irksome. Regardless, she humoured him, and helped Boruto through the initial stages of the game. While doing this, she began to realise what kind of person Boruto was.

During the setting for a special event, where Kiseki were gathered, Nanashi initially tried to discourage Boruto from participating. However, after he did, and won a 'winner' Kiseki, Nanashi had to set Zero's plan into action, utilising the Engraved Tsukuyomi to place the entire shinobi world under her mark. She then used Yachihoko to begin erasing the memories of everyone affected, and force them to prepare for the Fifth Shinobi World War.

Eventually, Nanashi was confronted by Boruto in Ninja Heroes, and when finally called out on her part in the chaos, Nanashi revealed her true appearance and face, fighting Team 7 within her Genjutsu. Having been fought off, Nanashi returned to Zero, and no longer wished to monitor the Genjutsu World of Ninja Heroes.

After the Yachihoko and its effects were broken, by the efforts of Team 7 and Toneri Ōtsutsuki, Nanashi was confronted by Boruto in Zero's hideout. Desperate to realise her dream and her plans, she fought against Boruto, who managed to break through to Nanashi, appealing to the good within her heart. Releasing that she cared for Boruto, Nanashi surrended. Because of her weakness, Teguse and Zero implemented their control device over Nanashi, forcing her to fight Boruto at full power. Naruto Uzumaki and Sasuke Uchiha intervened, saving Boruto.

Merz discarded Nanashi, and began to fight Naruto and Sasuke. Nanashi, however, used Yachihoko to give Boruto all of her gathered chakra, allowing Boruto to fight alongside his father and teacher and defeat Merza's Complete Body: Susanoo. She then died in Boruto's arms, imparting on him a Kiseki that had their combined memories and chakras.

When Boruto traveled back in time to the Warring States Period with the help of Toneri Ōtsutsuki, Nanashi's history was changed when Boruto rescued her from captivity. She fought alongside Boruto against her clan, earning her freedom with his help. Getting her to safety, Nanashi learned her true name from Boruto. Nanashi was able to live a modest and normal life away from war, and spent the rest of her life in gratitude to Boruto, even leaving an anecdote behind sharing how much he changed her life for the better.

Trivia

 * means "nameless" while her birth name means "light".