Sakura Matou

Matou Sakura (間桐 桜) is the sister of Matou Shinji. After Shirou's father Kiritsugu died, Sakura often visited Shirou's home to help him with his daily chores. She is outwardly shy and timid, but possesses great inner strength. Sakura has a long standing and obvious crush on Emiya Shirou.

Past
Born as Tohsaka Sakura, Sakura is the biological sister of Tohsaka Rin, and has been in the care of the Matou family for many years. Like most sorcerers, her father, Tohsaka Tokiomi, only chose one daughter to carry on his family's tradition believing that raising an additional child would introduce competition. Matou Zouken, an ancient ally of the Tohsaka House, offered to adopt Sakura, for his own heir, Matou Shinji, was incapable of sorcery.

In Fate/Zero it is revealed that Matou Kariya, now Sakura's uncle, made a deal with Matou Zouken to win the Holy Grail in exchange for her freedom from Zouken and to be able to return to the Tohsaka family. Kariya was the only member of the Matou family to love Sakura; since Kariya was a childhood friend of Tohsaka Aoi (Sakura's mother), he had become well-acquainted with Sakura and her sister. He was in love with Aoi, but gave up peacefully because she seemed to be happy accepting her engagement to Tokiomi. Since he never received training as a magus (though he had more potential in comparison to Shinji's father), he has worms implanted in him to boost his circuits, and underwent accelerated training for the coming war. The worms shortened his life span and constantly weakened body since they are eating away at his magical circuits. Considering his ever weakening body and the large mana requirement required for nature of his servant, a Berserker, it is not terribly surprising that Kariya loses the 4th Grail War, possibly at the hands of his own servant.

Under Matou care, Sakura is subjugated to physical and mental abuse on a daily basis. Zouken seeks to use her as one of his future vessels, empowered by the power of Angra Mainyu. Gathering the tainted fragments of the shattered grail from the last war, Zouken hybridizes the collected black ichor with several of his worm familiars. He implants these parasitic worms into Sakura's body; they drain her Mana but feed on her carnal impulses, drastically increasing her sexual frustration. To curb this aggravation, Zouken frequently instructs Shinji to rape Sakura. Jealous of Sakura usurping his birthright as heir of the Matou House, Shinji continues to brutally rape her of his own volition. Sakura's plum hair and eye color are direct consequences of Zouken's worms swimming through her bloodstream.

Although castigated and humiliated on a daily basis, Sakura maintains her bearings with great stoicism. She fell in love with Emiya Shirou several years ago after secretly watching him constantly attempt to jump a bar (as a track-and-field practice). His staying dedication inspires Sakura to endure her hardships, and her admiration gave her the confidence to approach and assist Shirou after he receives an injury. Shirou's growing relationship with Rin is a source of hatred and envy for Sakura, for she believes Rin to be the cause of all her torture. For the eleven years after her adoption, Sakura grew to resent Zouken for his cruelty, her father for sending her away, and finally Rin, who was unaware of her sister's suffering, for never coming to save her.

Sakura is the principal Master of Rider, who was summoned several days prior to the start of the 5th Holy Grail War. However, under pressure from Shinji and the desire not to fight either Shirou or Rin, Sakura yielded her Master's right to him, although Sakura retains her original Command Mantra.

Abilities
She has inherited tremendous sorcerous potential from her Tohsaka pedigree, although she has little knowledge of established incantations and her Mana supply is limited by Zouken's worms. On a whim, Zouken's can twist Sakura into a premature form of Angra Mainyu, referred to as "the shadow". In this state, Sakura's actions are below her threshold of awareness and are primarily directed by Zouken. However, once Sakura rejects Zouken's control and regains her central consciousness, she becomes Dark Sakura, a rancorous and psychotic distortion of her normal self. In this form, her reasoning and emotions are severely impaired and she is indiscriminately destructive to everything around her.

Dark Sakura has an unlimited supply of Mana, but the amount she can expel at any derivative is limited by her number of magic circuits. Her touch is highly corrosive, dissolving organic matter and converting the base elements into pure Mana. When an astral being, such as a Servant, comes into contract with Dark Sakura's shadows, that Servant's mentality is corrupted by her evil influence, while their offensive power is considerably augmented. She is also capable of forming tentacle appendages from her body, as well as birthing shadow monstrosities that follow her general intent but otherwise operate independently. Finally, Dark Sakura can spontaneously regenerate, allowing her to recover from mortal wounds within minutes of receiving them.

Role
Sakura only plays a minor supporting role in both Fate and Unlimited Blade Works, but she is the main female to the third arc, Heaven's Feel. Matou Zouken, disgusted at the ineptitude of Shinji as a Master, begins a genocide against the other Servants with help from True Assassin and Sakura. Berserker, Lancer, Saber, and Archer are all felled by this unholy trinity, and Sakura regurgitates Dark Saber and Dark Berserker as assistants. At night, she goes on a rampage throughout Fuyuki City, ingesting large numbers of innocents for Mana. Gilgamesh eventually confronts and impales Sakura's body with several Noble Phantasms from within his Gate of Babylon, but she regenerates at an impossibly fast rate and consumes him as well.

Recognizing the devastation she has wrought, Sakura seeks out her grandfather to force him into ending her life. Along the way, Shinji attempts to blackmail her into sex, threatening to tell Shirou of his history of raping her. Horrified at this prospect, Sakura kills Shinji and gives up to her internal evil. She then becomes Dark Sakura and abducts Ilya, hoping to use her as the core for a new Holy Grail.

After Shirou and Kotomine rescue Ilya, Dark Sakura kills True Assassin and purges her body of Zouken's worms. She is confronted by Rin in the chamber of the Greater Holy Grail beneath Mount Enzō, her power equally matched by The Jeweled Sword of Zelretch. Rendering Sakura's shadows useless, Rin makes her way to Sakura, but is unable to give the finishing blow due to her love of her sister. Rin embraces Sakura even after Sakura has stabbed her in panic. Realizing Rin's love, Sakura again starts resisting her evil long enough for Shirou to dispel Angra Mainyu's grip on her soul with Rule Breaker. Shirou then attempts to trace Excalibur but in True ending, Ilya intervenes, closes the gate, and performs the Heaven's Feel on Shirou to keep him alive (in Normal ending, Shirou does trace Excalibur and destroys the Grail, but his life extinguishes soon after. Sakura, refusing to accept Shirou's death, continues to live in Emiya house, forever waiting for Shirou).

After her dark self is destroyed, Sakura's body is left containing vast amounts of mana. She ends up living with Rider, with the servant's existence sustained by Sakura's mana pool.

In Fate/hollow ataraxia, Sakura lives a peaceful life in Fuyuki City, which Rin has left in Sakura's care while she is at the Mage's Association, and Rider comments that Sakura is now the popular new captain of the school archery club. Sakura's dark side still exists, but appears only for comic relief. In Eclipse, the bonus episode of Ataraxia, Rider and Sakura seem to work together to seduce Shirou and engage in a threesome with him. Actually this is all Rider's doing, trying to get Shirou to pursue Sakura more aggressively. Yet in the middle, Shirou realizes the truth and reverses her spell on her, in the end revealing to viewers that Rider herself has deep feelings for Shirou. Sakura appearing in this episode is only a conjecture by Rider's spell, a representation of Rider's true intentions of her actions.