Rider (Fate/stay night)

Rider (ライダー) is the Rider-class Servant of Sakura Matou in the Fifth Holy Grail War of Fate/stay night. Due to Sakura's unwillingness to participate as a Master, Shinji Matou is instead given control over Rider. She only truly acts as Sakura's Servant when their connection is revealed in the Heaven's Feel route.

Identity
Her real name is , the from Greek mythology. Medusa, along with her sisters, Stheno and Euryale, were born from the wishes of mankind for ideal goddesses, contrasting the flawed gods of Olympus. All three Gorgons were blessed with beauty, but unlike her sisters, Medusa was mortal, and fated to grow older and taller over time. Medusa was also cursed with Mystic Eyes, which transmute all living flesh under her gaze into stone, requiring her to wear a blindfold. Because of these differences, she was bullied by her older sisters. At one point, Medusa was given a Pegasus as a gift from Poseidon.

Jealous of the sisters' allure, Athena goaded the Gorgon's worshippers into attacking them, forcing the sisters to take refuge on the Shapeless Isle. This disgrace left Medusa bitter and spiteful of humans, her resentment intensifying as she killed invading men who lusted after her sisters. Over the years, Medusa became eager to slaughter and ingest humans, which spread infamy about her as an icon of terror. These fears, like the desires that gave birth to the Gorgons, distorted Medusa's appearance and incarnated her into the atrocious Gorgon of legend. Despite their teasing, Stheno and Euryale deeply loved their sister, and upon realizing they were responsible for her savagery, allowed Medusa to devour them. Eventually, the demigod Perseus, equipped with five Noble Phantasms, proved capable enough to decapitate Medusa, ending her tortured and dismal life. As she died, Medusa realized that however poorly Stheno and Euryale treated her, she had treasured the time she spent with them, and would later consider those experiences as her fondest memories. The Fate/stay Night universe also removes any references that the Gorgon sisters' hair were made out of living snakes, and thus Medusa and her sisters are depicted to have very long hair, instead of snake hair.

Personality
Rider is silent, sultry, and vigilant, never hesitating to shield her Master from harm. With Shinji incapable of lending any Prana to her, she is forced to seek alternative means to augment her abilities. In Heaven's Feel, she exhibits a strong desire to protect Sakura, even after her Master's death.

Fate/stay night
Rider's initial Master was Sakura Matou; however, she became the Servant of Shinji when Sakura, pressured by Shinji, yielded her Master's right to him. Rider holds no love for Shinji, seeing him as vile and predatory, but obeys his commands as a dutiful Servant. Because of their similar backgrounds, she is empathetic of Sakura, and seeks to protect her whenever possible. Like many of the Servants who participated in the 5th Holy Grail War, Rider has no motivation for seeking the Holy Grail.

Although regarded as one of the more powerful Servants of the 5th Holy Grail War, Rider is eliminated in almost every scenario. She is obliterated by Saber's Excalibur in Fate, and killed early on in Unlimited Blade Works by Caster's master, Souichirou Kuzuki.

Heaven's Feel
However, during Heaven's Feel, Rider is liberated from her indenture to Shinji, and assists Shirou Emiya in his battle against Saber Alter and Angra Mainyu.

Fate/hollow ataraxia
During Fate/hollow ataraxia, Rider is often found in Shirou's home, always engaging in her passion for reading. She aids the other Servants in holding back the invasion of Shadow Wolf Beasts during the Fuyuki eclipse.

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 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.

Abilities
Rider fights mainly with an unnamed dagger in close combat that resembles a large nail. It is not a Noble Phantasm, and while its origin is unknown, it is thought to be a weapon that reflects her inner character. She has the ability to summon a Pegasus as a mount, and it is far greater in power than a regular one.

She has three Noble Phantasms. Her main offensive ability is Bellerophon, which allows the Pegasus to use an extremely powerful charge that resembles an arrow of light. She can use it while mounted, or it can be launched directly from the summoning circle without having to ride it. She also has use of Blood Fort Andromeda, a Bounded Field designed to collect life energy from whoever is inside. Once it is set and activated, it can instantly liquify any normal humans inside and convert them into energy. Breaker Gorgon is another Bounded Field that seals the target inside the user's mind. She mainly uses it on herself in the form of a visor to seal her Mystic Eyes, though she does use it once on Shirou Emiya to take energy from him.

Cybele
Cybele (キュベレイ), the Mystic Eyes of Petrification (石化の魔眼), are Rider's Mystic Eyes. Though petrification sorcery is no strange thing for modern Thaumaturgy, even if its users are rare and few in numbers, Mystic Eyes capable of petrifying others are something that nobody, human or not, possesses in the present era. They are designated as Jewel under the Noble Colors system, which surpasses the Gold-ranked Eyes of the Dead Apostles and are exclusively possessed by Holy Spirits and Magical Beasts from the Age of Gods. Their nature is strong enough a mystery that Shirou mistakes the identity of Breaker Gorgon as the eyes themselves. Her eyes are normally sealed by Breaker Gorgon in order to hide her identity and keep them from constantly affecting others, and she is able to fight much more effectively after it is released. She later uses Mystic Eye killing glasses after Heaven's Feel's and during Fate/hollow ataraxia.

The eyes, almost too abnormal to be called eyeballs, are gray with an appearance similar to crystals. Despite their abnormality, Shirou believes that they are too beautiful for any human to posses, and could either be art the gods admired or a nature they cursed. The corneas do not take in light, and the pupils see the world through a square. The irises are solidified, not allowing the eyes to close, and the millions of cells that make up the retinas are composed of the Sixth Imaginary Element. It affects all targets within the owner’s field of vision, regardless of whether said targets are looking at the Eyes physically, or if they have their eyes closed but continue to view her with their mind's eye, as it is a curse to look upon her in any way. The only way Perseus was able to avoid her gaze was by utilizing his mirror shield to find her location without looking upon her.

Those who possess Rank C or lower in Mana will be immediately petrified, while those with Rank B may or may not be affected depending of the conditions. Those with Rank A or higher won’t be petrified, but will sustain "pressure" from the Eyes and receive a one rank-down to all parameters. When Archer, with Rank B Mana, is affected at close range, he instantly feels the effects. He is immediately is frozen in place, unable to close his eyes or cover them with his arms even if he wanted to do so due to being unable to move either in the slightest. He tries to charge at her afterward, but his legs are already petrified up to his knees at that point. He is petrified up to his waist only a moment later.

Shirou feels the effects from further away, as his blood starts thickening. It starts solidifying the flow of his body and ceasing his senses. If he tries to run at her, his body is instantly turned to stone, and his mind swiftly follows. He is only saved when Sakura acting up causes Rider to cease her activity. Due to his knowledge of the eyes, further attacks would not be as effective. It is not enough to allow Rider to go without Breaker Gorgon in his presence, but repeating the initial surprise effect would be impossible. He won't instantly go numb and the effect of petrification would go at a slower rate, but it would be magnified if he let his guard down.