Rider

Bio

She is the Servant of Shinji, first seen scouting around Homurabara Gakuen. Rider is silent, sultry, and vigilant, never hesitating to shield her Master from harm. With Shinji incapable of lending any Mana to her, she is forced to seek alternative means to augment her abilities. To compensate for this weakened state, Rider employs covert battle tactics and takes full advantage of any territory around her. Her weapon of choice is a pair of long iron nails fastened to opposite ends a single chain, which she effectively thrusts from distances.

Her real name is Medusa, the Gorgon 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 Pegasus as a gift from Poseidon.

Jealous of the sisters' allure, Athena goaded the Gorgon's worshipers into attacking them, forcing the sisters to take refuge on the Shapeless Isle. This disgrace left Medusa bitter and spiteful of humans, her resent 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.

Rider's initial Master was Sakura; 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, Kuzuki Souichirou. However, during Heaven's Feel, Rider is liberated from her indenture to Shinji, and assists Emiya Shirou in his battle against Dark Saber and Angra Mainyu.

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 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.