Izumi Uchiha

was a kunoichi from Konohagakure and a member of the Uchiha Clan. She was a friend of Itachi Uchiha since their childhood, and was infatuated with him.

Background
Izumi was born into the Uchiha clan, as her mother was a member but her father was not. Izumi was not a recognized member of the clan due to her mother leaving the clan to marry her father, though she kept the Uchiha name.

In the anime, Izumi meets Itachi prior to them enrolling in the academy, where she asks him to join her and her playmates in a game, but he declines. When the other children begin bullying Itachi, she defends him and orders them to leave him alone, but Itachi scares the bullies when he deflects a rock back at one of the bullies before leaving. On the night of the Nine-Tails rampage, Izumi is crying out for her parents and is found by Itachi who saves her from being killed by debris. Along with the infant Sasuke, they take refuge in a shelter. Afterwards, she thanks Itachi for saving her and asks if she can hold Sasuke, to which Itachi refuses because she will make Sasuke cry. Izumi persists but Sasuke cries and Itachi takes him back, which makes Sasuke happy, but this leaves Izumi irritated.

On the day of the Academy Entrance Ceremony, Izumi happily waves to Itachi and she, along with a majority of the girls at the Academy, watches Itachi from afar and develops a crush on him. Itachi, however, shows no interest in her feelings and maintains an aloof exterior around her.

After Itachi graduates early and becomes a genin, he meets Izumi and they sit by a lake while she offers him some of her dumplings. Itachi initially declines but is unable to resist, leading Izumi to find it amusing someone as mature and skilled as Itachi has a soft spot for sweets. She apologises for not getting him a graduation present but he says it's not important. She asks him if there is anything he would like and she correctly guesses he wants to awaken his Sharingan as he stares into her eyes, implying she already awakened hers. Tenma comes to pick Itachi up for a mission and tells them to stop flirting, and Izumi retorts they were not. Izumi then tells Itachi she believes he will awaken his Sharingan and she will pray for him.

In the novel, Izumi witnessed her father sacrifice himself to save her and her mother during the Nine-Tails' attack, which awakened her Sharingan. Afterwards, Izumi and her mother returned to the Uchiha clan as it was being forced to relocate to the outskirts of Konoha. She met Itachi shortly after they enrolled in the Academy and developed a crush on him but he shrugged her off. When Itachi was bullied by classmates who blamed the Uchiha for the Nine-Tails' attack, Izumi defended him and showed him her Sharingan and how she awakened it. Izumi graduated from the Academy at age eleven, a year early, and thus allowed her to spend more time with Itachi. While they were at a tea shop, Izumi told him that she wanted to become a strong ninja and protect others from hate, but Itachi hurt her feelings by criticizing her.

During the Uchiha Clan Downfall, Itachi came to her to begin the massacre with her as he was told by Danzō Shimura that he could only spare his little brother Sasuke Uchiha. Believing that ending her life first would quell his inner doubts, he proceeded to kill her and her mother first. As he lured her mother away, Itachi approached Izumi and placed her in an extremely powerful Tsukuyomi where she lived the entirety of her life in 0.000000001 billionths of a second. In her dream, she became a chūnin, retired from shinobi life to become Itachi's wife and raise their children, and lived to become eighty years old before dying of old age alongside Itachi. Because her mind was departed from reality in such a manner, Izumi collapsed into Itachi’s arms dying. Izumi thanked Itachi for giving her the life she wanted with him, even if it was a dream, and Itachi thanked her for loving him as she passed away

Personality
Izumi was described as a kind and considerate girl for an Uchiha. After her father’s sacrifice, Izumi was traumatised and blamed herself. Since then, she decided to live up to her father’s example by becoming stronger so she could help others like her father did. Because of this, Izumi never fell into the Curse of Hatred, unlike the vast majority of her fellow clansmen. Even though she appeared to distrust the rest of her clan like Itachi and Shisui Uchiha, she still had great pride and faith in her clan as she refused to believe an Uchiha would’ve summoned Kurama to cause such death and destruction that took her father’s life.

Her desire to help others weighed heavily on her, as she was deeply distressed she wasn’t progressing as quickly as Itachi, who she used to measure her abilities against. When Itachi tried to convince her to abandon her goal of helping others because of her innocence and weaknesses, she was visibly hurt.

Izumi was deeply in love with Itachi, so much so that she accepted Itachi's decision to end her life for the sake of the village, and was grateful to be given the life she wanted with him: growing old and having kids together, even if it was only a genjutsu.

Appearance
Izumi had long brown hair (in a ponytail in her youth) with bangs framing her face and onyx eyes, with a mole under her right eye. She wore a long-sleeved, high-collared purple shirt with the Uchiha clan symbol on the back, baggy blue pants, a shuriken hostler on her right leg, red armband on her left arm, and a long purple fingerless glove that ran nearly the length of her arm.

Abilities
When her father died during the Nine-Tailed Demon Fox's Attack on Konoha, she awakened her Sharingan, even earlier than Itachi himself. However, she was not able to handle it for long, quickly fainting every time she activated it as she lacked the necessary chakra levels. This did not get better as she still fainted even when she was getting closer to her graduation into genin. In the anime, it was noted that she had especially advanced taijutsu prowess. It was implied that Izumi was skilled as a kunoichi for graduating a year earlier than others.

Itachi Shinden: Book of Bright Light
In her early Academy days, she learned that she would be classmates with Itachi, where she became infatuated with him. Eventually, she earned his acceptance when she defended Itachi from older Academy students like Tenma Izumo (one of Itachi’s future team-mates), who was jealous of his advanced skills by using his Sharingan.

When she was eleven years old and about to graduate early, Izumi and Itachi stopped at a tea shop for a rest where Itachi's former team-mate Shinko Inari was now a waitress at. Here Itachi questioned her on her desire to grow stronger. She explains her desire to grow stronger to help others is inspired by her father’s sacrifice, but Itachi’s insistence on her abandoning her resolve made her cry and she left. Eventually, Izumi and Itachi were seen as a "couple" by many of their peers.

Itachi Shinden: Book of Dark Night
During the Uchiha Clan Downfall, she was Itachi's first victim, being killed in a peaceful manner.

Trivia

 * means "fountain".
 * In the anime, Izumi's death is altered to being killed by Obito Uchiha when she confronts him outside the Konoha Military Police Force's Headquarters.