Sakura Matou, originally Sakura Tohsaka, is the biological younger sister of Rin Tohsaka, born to Tokiomi Tohsaka and Aoi Zenjou. Adhering to magus traditions allowing only one heir, her father arranged her adoption into the Matou family as a child to become their magecraft successor, replacing their biologically heir Shinji Matou who lacked magical aptitude. This adoption severed her ties with her biological family under orders from her adoptive grandfather, Zouken Matou. Her life in the Matou household subjected her to extensive physical and psychological torture. Zouken implanted parasitic Crest Worm familiars into her body, draining her magical energy while feeding on her carnal impulses. This painful process altered her appearance, changing her hair and eyes from black-brown and teal to violet, and amplified her emotional responses, particularly jealousy and repressed desires. She also endured years of sexual abuse from Shinji Matou, who resented her for replacing him. Her adoptive uncle Kariya Matou attempted to rescue her by participating in the Fourth Holy Grail War but failed and died; Sakura misinterpreted this as a warning against defying Zouken, deepening her resignation. Emotional resilience partially stemmed from observing Shirou Emiya's persistence during track-and-field practices. After Shirou sustained an injury two years before the Fifth Holy Grail War, she approached him to offer help, initiating regular visits to his home to assist with domestic chores. These interactions gradually restored her emotional expressiveness, though underlying resentment toward Rin for never attempting to save her and toward Tokiomi for abandoning her remained. She joined Homurahara Academy's archery club to be near Shirou, developing a deep romantic infatuation. Her jealousy surfaced when he interacted with other women, compounded by low self-esteem and the Crest Worms' influence. In the Fifth Holy Grail War, Sakura was Rider's true Master but transferred command to Shinji via a Command Spell due to her reluctance to fight. Her latent Imaginary Numbers magecraft, a rare form enabling manipulation of interdimensional space and connections to demonic entities, remained undiscovered. Crucially, she unknowingly hosted a fragment of the previous Grail, implanted by Zouken, transforming her into the "Black Grail." This connection allowed the corrupted Servant Angra Mainyu (Avenger) to manifest through her as a destructive entity known as "The Shadow" during her sleep, consuming lives to gather energy. During the Heaven's Feel route, Sakura's psychological fragility escalated. After Shinji attempted to rape her, she fused with The Shadow, becoming "Dark Sakura." This transformation amplified her long-suppressed rage, envy, and destructive impulses, leading her to kill Shinji. As Dark Sakura, she exhibited a split personality: one aspect retained her love for Shirou, while the other sought vengeance. She kidnapped Illyasviel von Einzbern to use as a Grail vessel and deployed corrupted Servants like Saber Alter and Berserker against allies. Her conflict culminated in a confrontation with Rin, whom she stabbed after Rin admitted she could not kill her sister. This act triggered Sakura's realization of Rin's enduring love, causing temporary control over The Shadow. Shirou Emiya, determined to save her, utilized the projected dagger Rule Breaker to sever her link to Angra Mainyu, freeing her from The Shadow's corruption. Afterwards, Angra Mainyu's emergence from the Grail threatened Fuyuki City. Shirou intended to destroy the Grail at the cost of his life, but Illyasviel sacrificed herself using the Heaven's Feel ritual to destroy it and preserve Shirou's soul. Sakura survived, and Shirou's soul was later restored into an artificial body by Rin and Touko Aozaki. In the route's True End, Sakura lived peacefully with Shirou and Rider. The Normal End depicted her descending into madness after Shirou's sacrificial death, living alone in the Emiya household awaiting his return. Beyond Heaven's Feel, Sakura appeared in sequels and spin-offs. In Fate/hollow ataraxia, she became head of the Matou household, ousting Zouken, and grew more confident as captain of her archery club. She maintained weekend stays at the Emiya residence, though jealousy toward Rin and other women persisted. Occasional manifestations of her "Dark Sakura" persona served as comic relief. In Fate/kaleid liner Prisma Illya 3rei!!, she appeared as a mind-controlled doll used by the Ainsworth family to attack Shirou. The prequel Oath Under Snow depicted an alternate timeline where she participated in a parallel Holy Grail War using a Gilgamesh class card but was killed by Shinji. Sakura's abilities center on Imaginary Numbers magecraft, enabling spatial manipulation and energy absorption. As the Black Grail, she could corrupt and control Servants like Rider, Saber Alter, and Berserker. The Crest Worms granted accelerated healing and mana absorption but left her vulnerable to Zouken's manipulation until she extracted and destroyed him. Her design features long violet hair tied with Rin's ribbon, a reserved demeanor, and a developed physique. As Dark Sakura, her appearance shifts to pale skin, dark attire, and a menacing aura accentuated by ufotable's animation.