<Dd> A solitary Servant, clothed in a traditional Japanese hakama and kimono with an indigo haori . This handsome man bars entry beyond the main gate of the Ryuudou Temple . Quiet and composed, he maintains a degree of bushido and is eager to spar with other Servants . He is of the same class, but he is not to be confused with another Servant known as True Assassin . He initially claims to be Sasaki Kojirō (佐々木 小次郎, Sasaki Kojirō), but in reality he is a nameless samurai "who forged his past and is a master swordsman only in people's memories". He was summoned by Caster as a guardian and watchman for the front gate of the Ryuudou Temple . As an improper servant, Assassin is entirely dependent on Caster for mana and cannot move freely beyond the grounds of Ryuudou Temple . Furthermore, he lacks most of the usual parameters and abilities granted to his class . Because of his limited status, Assassin cares little for the Holy Grail, and outside of his duties to Caster, he only seeks to enjoy a decent sword fight . His special move is the Turning Swallow Strike (秘 剣 ・ 燕返し, Tsubame Gaeshi), an unblockable attack that hits from three directions simultaneously, reaching into parallel dimensions . It is a sword skill of the highest degree that requires no mana other than that needed for Assassin to move, and as such is incredibly efficient . It is a sure - kill move, although in a different sense from Gáe Bolg . Its one weakness is that it can only be executed with a level foundation and enough space to maneuver - otherwise, only two simultaneous strikes are possible . </Dd> <Dd> In the Fate route, his ultimate fate is unknown, but Caster comments that he disappeared . In Fate / Hollow ataraxia, he is described as having been killed by Gilgamesh during what appears to be the Fate Route . In the Unlimited Blade Works route, he faces Saber once after letting Shirō and Archer pass in order to let them cause inconvenience for Caster, later letting Saber leave with her Master after Shirō is wounded by Archer as a sign of respect for her abilities and desire to defend her comrade . He is defeated by Saber on the last night of the Holy Grail War due to his blade being bent from their previous encounter, which leaves an opening in Tsubame Gaeshi that she takes advantage of . In the Heaven's Feel route, Assassin's flesh serves as Matō Zōken's catalyst for summoning True Assassin, with the latter bursting out from within his flesh . </Dd> <Dl> <Dt> Caster (キャスター, Kyasutā) - Medea (メディア, Media) </Dt> <Dd> Voiced by: Atsuko Tanaka (Japanese); Tara Platt (Fate / stay night, UBW film), Megan Hollingshead (UBW TV) (English) </Dd> <Dd> She is an honored guest of the Ryuudou family, permitted to live at their temple until the preparations for her marriage have been finalized . Her true identity is Medea, the disgraced princess of Colchis who was branded a witch as a result of actions outside her control . A gorgeous and talented yet mysterious woman of high stature, her presence has attracted the attention of trainee priests and even Issei . Unlike other Servants, she does not wield a weapon for physical combat, but her rank allows her to manipulate Mana and perform magic like a wizard, something which other Servants cannot do . Her magical ability far surpasses modern Magi, due to her technique, High - Speed Divine Words (高速 神 言). This allows her to cast spells which would normally take minutes to cast by uttering a single word . In the anime and the Unlimited Blade Works route of the visual novel, she easily blocks Rin's Gandr shots and can teleport herself and her Master out of harm's way . Because of her Magus ability, she has a dual role as a Servant to Kuzuki, and a Master of Assassin . Her Noble Phantasm is Rule Breaker: Destroyer of all Talismans (破戒 す べき 全て の 符 (ルール ブレイカー), Rūru Bureikā), an otherwise weak dagger which dispels all forms of magic that it comes in contact with . Its greatest use is in severing the bond between Master and Servant . She also possesses a Noble Phantasm called Argon Coin: The Golden Fleece (金 羊 の 皮 (アルゴン コイン), Arugon Koin), a coat of golden fleece which is capable of summoning the original Colchis dragon that guarded it after it is thrown upon the ground . However, Caster does not have the knowledge or skill to summon a phantasm - beast, so it goes unused during the Fifth Holy Grail War . If she did possess the proper skills necessary to summon the dragon, it would bring her up from being the weakest Servant to the middle - ranking among the Servants of the Fifth War in terms of frontal combat ability . The dragon itself isn't strong enough to be able to make a clear difference against higher level opponents . </Dd> <Dd> In the Fifth Holy Grail War, shortly after her summoning, she kills her original Master Atram Galiast within a few days, and is later taken in by her current Master Sōichirō Kuzuki at the Ryuudou Temple . Caster quickly fell in love with Sōichirō, for he was the first man to show her genuine kindness, dedication and loyalty . Her primary objective shifted from obtaining the Holy Grail for herself to simply preserving their short time together . To that end, she takes the souls of other beings to sustain herself and strengthen her defensive power, as Kuzuki is incapable of providing her with Mana . </Dd> <Dd> In the anime - original storyline, she kidnaps Sakura by possessing her body and stabbing Saber with Rule Breaker, but, because of Saber's A-ranked magic resistance, she was only able to take away Saber's ability to use her Noble Phantasm . She then tries to sacrifice Sakura, who has latent Magus abilities, to summon the Holy Grail directly . She is then defeated by Gilgamesh's Gate of Babylon in her underground city . In the Fate route, she is defeated by Gilgamesh's Gate of Babylon while attempting to attack the Emiya household . In the Unlimited Blade Works route, she is the primary antagonist of the first third of the route . She personally stabs Saber with Rule Breaker, turning her into her Servant for a short time, but is later betrayed and defeated by Archer, who showers her with a barrage of Noble Phantasms from Unlimited Blade Works . In the Heaven's Feel route, she is killed by Saber early on after losing Assassin and Kuzuki in an attack by the Shadow, but Matō Zōken uses one of his worm familiars to maintain her body as a puppet for a brief period of time before it is slain for good by Saber . </Dd> </Dl> <Dt> Caster (キャスター, Kyasutā) - Medea (メディア, Media) </Dt>

Who are the servants in fate stay night based on