Sakura Matou (間桐 桜, Matō Sakura?) is the Sakura Matou of the alternate reality from which Miyu Edelfelt and the Ainsworth family originate. She is the Card User of a Berserker Class Card from an unknown Ainsworth Holy Grail War.
At some point in the past, Sakura's daily life seemingly mirrored that of her usual counterpart, going to school and taking part in Archery club activities. While the extent of her relationship with Shirou Emiya is unclear, it is apparent she had developed a strong infatuation with him at some point in the past.
During the period of the Fifth Ainsworth Holy Grail, she was given an Archer Class Card that was supposed to be the Card of Gilgamesh and she wanted to give it to Shirou in order to allow him to participate in the war. They are attacked by her deceased brother, Shinji Matou, whose mind was placed into a Doll body. As she tries to Install the Card to protect Shirou, it's revealed that it was only a Nameless Class Card because the Ainsworth were aware that she would eventually betray them.
She is ultimately killed by Shinji's Assassin Class Card's Noble Phantasm, Zabaniya: Dead Heartbeat Melody and her body is engulfed by a black shadow. She later receives the same treatment as her brother and is place into a Doll body and is given a Berserker Class Card to act as a war doll.
Having her personality damaged after being brought back to life, Sakura appears to be mentally unbalanced, possessing an obsessive disposition towards the Shirou Emiya of her world. This goes to the extent of wishing to kill those who she perceives as getting in the way of this relationship. She considers herself the only one who can truly understand and love Shirou, the only one who can touch him and in turn be touched by him and when pushed, the only one permitted to kill him.
This imbalance is exploited by Julian Ainsworth, who, taking on Shirou's image, manipulates Sakura to do his bidding. When being spoken to by Julian's illusion, Sakura becomes distinctly more placid, accepting his instruction with minimal resistance. At this time, she seems to be under the impression that she still had club activities to perform, and when corrected, states that she has been absent minded of late, showing a somewhat disassociation between herself and the current situation.
Fate/kaleid liner PRISMA☆ILLYA 3rei!!Edit
As a Doll, Sakura first appears as the last line of defense for Julian when Shirou attacks him. Seemingly appearing from the mud below Julian's feet, she attacks using the power of the Berserker, Lancelot. Catching him by surprise, she severely wounds him. Stating that she had been waiting for him a very long time, she is attacked from behind by Miyu, who uses the Archer class card to attack.
Despite the onslaught of weapons Miyu uses, Sakura is able to take control of them. Before Miyu can launch into another barrage however, her personality starts to be overtaken by that of her own class card, and Julian interrupts, taking the Archer card from her.
No longer possessing that power, Sakura proves overwhelming, nearly killing Miyu before Julian once again intervenes. Using the power of his Assassin class card, Julian restrains Sakura and, taking Shirou's image, convinces her to halt her assault. She is last seen being dragged back into the mud by the Assassin's Noble Phantasm.
She is brought back following the return of the Ainsworths in order to act as guard of the pathway leading to Julian and Pandora's Box. She becomes the opponent of Chloe von Einzbern and Miyu who were trying to pass her vigilance.
Sakura seems to be imbued with the powers of Lancelot of the Lake, as he appeared in Fate/Zero. Whether this ability has been granted from a class card, or via interacting with the mud from which the corrupted heroic spirits appeared, is unclear. Regardless, it gives her use of Lancelot's most devastating skill Knight of Honor, which allows her to use the armaments of others as her own, making her particularly effective against the likes of Shirou Emiya and Gilgamesh.
As a member of the Archery Club, it could also be assumed that she has some ability with a bow and arrow. It is unknown if this version of Sakura has any ability with Magecraft normally.