Arturia Pendragon:
Character History:
Arturia was born into a time of chaos and war that began with the demise of the Roman empire, with Arturia's mother speculated to have had roots that traced back to it. It had been believed that the Roman empire was indestructible, but had in fact been only awaiting it's destruction at the hands of the invading barbarians. In preparation for war against the barbarians, Rome deprived it's island province of any military forces left there - and once Britannia lost the empire's protection, it could not escape becoming independent, causing it to break into smaller countries soon after.
The time of the barbarian invasions an self-destructive strife between clans started a long period of war that would later become the "Dark Ages." Arturia was born into this period as heir to the throne, the daughter of the King of Britten, Uther Pendragon, and the blue-eyed Igraine, wife of Uther's servant - the Duke of Cornwall. The king, believing in a prophecy given to him by the wizard Merlin, yearned for the birth of his appointed successor, but the child born - a girl - was not the heir he desired, as females were not allowed to be warriors, let alone take the throne. Thus, even if she was fated to be king, Uther could not make Arturia his heir and was subsequently entrusted to the king's vassals and was to be raised as the child of a mere knight. The king fell into despair at the situation, but Merlin was delighted because the gender of the one to become king had never mattered, and was confident of the fact that the girl being separated from the castle until the day of prophecy was proof that she would become king.
Arturia was placed by Merlin into the care of Sir Ector, a simple and wise old knight who raised her as his adopted child and successor. Although Ector did not believe in the prophecy, he did feel the same air from the girl as he did his king Uther, so he felt that he must raise her as a knight, wishing for her to grow. He never needed a wish for such a thing it turned out, as she trained day after day to become stronger then anyone, swearing to bear her sword for only one reason - a that she formed of her own validation: "only a king can save a ruined country headed for death." During this time, she was raised with Sir Kay as her brother, but they still loved each-other as siblings even after they learned the truth of her adoption. Arturia acted as his squire and received training from him, while also doing other chores such as pulling along his horse. Arturia was better then Kay in terms of swordsmanship, but she never beat him in a fight due to his arguments declaring himself the winner rather then actual skill.
Once the day of prophecy arrived, Knights and Lords from around the country gathered to be selected as king. Each expected the selection to be through jousting to select the most superior one to become king - but the only thing prepared at the place of selection was a simple naked sword stuck in a stone with a golden inscription on the hilt, reading "Whosoe'er pullet out this sword of this stone is rightiwise king born of England." While many knights grabbed the sword trying to follow the command, none were able to pull it out. As they began the expected method of selection by jousting, Arturia, only an apprentice not qualified for jousting, neared the deserted stone of selection and reached out for the sword without hesitation.
Before grabbing it though, Merlin appeared before her to tell her to think things over before taking it, warning her that she would no longer be human upon taking hold of the sword - but she only responded with a nod because she had been prepared for the fact that "becoming a king means no longer being human" ever since she was born. She knew that a king was someone who kills everyone to protect everyone, and thought about it every night and shuddered until morning came. While not one day passed where she did not fear that fact, Arturia said it would end this day - and thus, the sword was pulled out as if it were only natural to do so, and the area was filled with light. Arturia became something that was not human in that instant - the king's gender did not matter, and no-one will care about the king's appearance or even notice it as long as the king acts like a king. Even if anybody did notice that the king was female, it would not be an issue is she was a good king. Thus, this act started the time of the king who would become a legend.
Arturia led Britain from Camelot, and after becoming a feudal lord like her father Uther, she became a king with many knights under her, including the esteemed Knights of the Round Table - Lancelot, Gawain, Mordred, Ector, Bedivere, Percivel, Boris, Galahad, Kay, Lionell, Gareth, Tristram, Bleoberis, Lucan, La Cote, Palomedes, Lamorak, Safer, Pelleas, Dagonet, Degore, Brunor, Le Bel, and Alymere. Arturia's growth stopped at that time because she pulled the sword and because of it's potent regenerative magics, so many knights thus feared the sword as "ominous." Most instead praised their master's immortal appearance as divine. Her battles thereafter were the acts of a god of war - she always led them from the front, and no enemies could stand in her way. There was no defeat for a body armored as a dragon's in human form, and she only knew victory for ten years and twelve battles while she ran through those days as the king, never turning back and never being disgraced. She was raised as the king, and she fulfilled her obligations as the king.
However, the problem of being able to produce an heir for her legacy was one that persisted for some time. Merlin used magecraft to turn her into a male capable of producing sperm with which to provide an heir from, and she stayed in that state for an unknown period of time - during which, she fell victim to the machinations of Morgan le Fay, her half-sister, who's plotting would eventually lead to their mutual ruin. Morgan wished to claim the throne for her own, believing that Arturia had stolen what had rightfully been hers through succession by simply pulling free the sword from the stone, and thus bewitched and seduced Arturia, concieving a child from the unholy union, and through magecraft, she turned the unborn child into a homunculus clone of Arturia - a child that would one day become the Knight of the Round known as Mordred, who was born and raised by Morgan without Arturia's knowledge, quickly growing up due to her accelerated aging and going on to Join the Round Table through her own efforts and Morgan's recommendation.
Mordred worshiped Arturia while hiding her identity, and was ecstatic to learn of her heritage. However, when Mordeed revealed her heritage to Arturia and made her claim to be heir, Artutia completely rejected Mordred and refused to recognize her as an successor, with Mordred believing the reason she was not accepted was because Arturia hated Mordred's mother Morgan for the circumstances behind her cursed birth - and that no matter how much Mordred would excel over others, she would forever be considered a tainted existence by her father. The love that Mordred had for the king had up until that point was so great that the through rejection made her hatred burn like a wildfire.
Arturia eventually married a woman named Guinevere, but only out of obligation to have a wife. The truth was that Guinevere and Lancelot, one of Arturia's closest friends, loved each other, and due to Arturia having concealed her gender, Guinevere had to carry the burden of never being able to pursue those feelings for the rest of her life. Guinevere felt guilt for doing such a thing to Lancelot, but felt relief that Lancelot did indeed love her, and Lancelot, who shared the same ideals as the king, would share the burden with her and not cause the country to fall into a dangerous situation. Thus, Lancelot supported Guinevere and Arturia from the dark on his admittedly unrighteous path. Arturia needed to act as the son of the king - as the one to govern them many territories and control the knights had to be male. While some people did grow suspicious of her, only her father Uther, Merlin, and Kay knew the exact truth of her identity and gender. She literally covered herself in steel to seal that truth for all her life, and due to her immortality to the passage of time from the protection of the fairies, no-one questioned her small body or feminine face.
She was honored by the nights as a good-looking king, thought of as an invincible warrior who's looks or body size had an impact on her standing. During that time, the people living in fear of savage barbarian invasions had only wanted a strong king, and the knights would only follow an excellent commander, and as Arturia met these criteria, no one questioned her - she was considered fair and selfless as she always stood at the front of the army while defeating her enemies on the battlefield. While many enemies and civilians died, the king's choices were always considered correct, and she served as the king better then anyone else - no-one doubted or had any need to doubt as long as the king was right. Under her leadership, Arturia's army reconstructed the lost cavalry, and knowing no losses, they ran through the battlefield while defeating foreign infantries and crashing through numerous ramparts.
Many people were discarded for her to join the battles, and all her enemies had to be defeated once she joined - it was common practice for the military to meet it's needs my sucking out all the resources from a local village to supply the battle and protect the country, and it can be said that no knight killed more people then her, though it is unknown if she ever found that to be a burden or not. Arturia strictly kept to the oath that "a king is not human and that one cannot protect the people with human emotions." She never narrowed her eyes in grief while sitting on the throne, and she settled every problem while working hard in government affairs. She managed to balance the country without any deviations, and she punished people without a single mistake.
But, in spite of all her accomplishments - even after, or possibly even because of, winning battles in endless victory, commanding citizens without disorder, and punishing hundreds of criminals, one of her knights would murmur the words that would serve as the catalyst of her downfall - "King Arthur does not understand human feelings." In truth, it is possible that everyone truly felt that way about her, and that the more perfect she became as a king, the more they would be able to question her as a ruler. They began to feel that a human without emotion cannot truly rule over others because they cannot understand the feelings of human beings, leading to several reputable knights leaving Camelot, while others such as Mordred would silently stew in discontent - though none had truly been scorned like Mordred had at that point in time. Arturia simply accepted this to be a natural event that was part of the process of government, isolating the fair king honored by her knights. Having abandoned her emotions from the start, she did not change her mind even if she was abandoned, feared or betrayed - there was no right or wrong to someone who saw such events as trivial.
Her final battle for her country began in such a way, with the battle at Badon Hill ended in complete victory - the savages sought reconciliation due to Arturia's overwhelming results, and the country that was only awaiting destruction earned a brief period of peace in which it finally began to return to the country of which she had dreamed. But, ultimately, it was not to last - during her travels, Arturia lost herself one time and broke the rules of chivalry in battle, and as a result, Caliburn, the sword she had pulled from the stone that had made her king, broke during the fight. She eventually had the blade replaced with Excalibur and the scabbard Avalon - but her troubles were far from resolved, as Lancelot's affair with Guinevere was eventually reveled at last through the plans of traitors who hated Camelot, causing them to stand opposed.
Arturia did not see this inescapably unrighteous action as a betrayal, but instead understood Guinevere's sacrifice due to having concealed her gender - however, she still acted in the capacity of a king, and Guinevere was put to death. But Lancelot could not stand idly by while Guinevere was killed, and, grieving and heartbroken, fought through his fellow knights to rescue her, slaying Gareth and Gaheris - the brothers of Gawain - in the process. Lancelot - the perfect knight disgraced - Guinevere - the queen branded an unfaithful adulterer - and Arturia - a king who could not even see it happening, or worse may have allowed it - all suffered from the political fallout, which only was made worse when Arturia spared Lancelot from a trial and execution. This fractured the loyalty of the Round Table, as, between Lancelot's actions and Arturia refusing to execute him for it, the knights of Camelot were finally shown an event where their king had made a misstep - with the strongest voices being Gawain and Mordred. Gawain was angered that Lancelot was allowed to go alive, but still loyal to his king - Mordred however was absolutely enraged that Arturia could seem to forgive Lancelot's actions of murdering fellow knights and having an affair behind the King's back, yet spurn Mordred when she was the king's own flesh and blood, and thus Mordred became the leading voice of discontent with Arturia's rule. Ultimately, it was a tragedy in which nobody was right, and nobody was wrong.
Seeing the weakness of Camelot, enemies along the kingdom's borders became emboldened and made their move, assaulting the bordering lands. Arturia left on the Rome Expedition, moving to repel the invaders along the way - and no sooner had she done so then the final pieces of her downfall began, as Mordred launched a sudden and surprisingly successful coup attempt, shocking those loyal to Arturia with how utterly successful Mordred was at galvanizing the people against their king and fueling their discontent with the fractured loyalties of the kingdom in the wake of Lancelot's actions.
Mordred successfully took command of the throne and the kingdom, breaking into the royal armory and stealing Clarent - the sword of Arturia's father Uther - for herself, as a symbol of having usurped her father as the King of Camelot. When Arturia returned inland, she found Britain torn asunder by civil unrest as the loyalists to her throne fought bitterly against the forces of Mordred's rebellion. In order to secure her child's success, Morgan managed to orchestrate the theft of Avalon, the scabbard of Excalibur, ensuring that Arturia would not have it's divine protection when she finally faced Mordred. On the eve of this fight, Lancelot returned, offering to fight by her side at the battle to try and make up for his actions, but he was denied by an angered and embittered Gawain - and in doing so, Gawain unknowingly sealed the final nail in Arturia's demise.
The battle between Mordred and Arturia's forces, known as the Battle of Camlann, was fierce and brutal, with the majority of the knights dying amid the chaos and the flames. They carved a swath through each-other's forces, with Mordred's guard eventually killing most of the knights loyal to Arturia - including Gawain, who was felled at the hand of one of Mordred's loyalists, dying in tears as he lamented not allowing Lancelot to fight with them and that his anger would cost Arturia her life. Eventually, the armies decimated each-other and the core of the kingdom burned wildly, until only Mordred and Arturia were left standing upon a flaming hill covered in fallen swords and the bodies of their comrades.
Mordred, gesturing to the burning landscape, denoted that the fight was now pointless - the kingdom was all but destroyed, so it no longer mattered who won, with the efforts of both having been for naught. Blaming Arturia for not giving her the crown, Mordred asked why she couldn't have been king and if Arturia truly hated the "Son of Morgan" so much. However, Arturia, ever emotionless and stone-faced, replied that it had nothing to do with Mordred's birth and that she had never hated Mordred - she had simply not seen the capacity in Mordred to be a king. Enraged at the prospect of having never been good enough for Arturia from her own merits rather then her birth and the seeming lack of acknowledgement of her as a person, child or heir, Mordred charged at Arturia and the two engaged each-other in a final battle.
Eventually, Arturia was able to defeat Mordred, slashing her helm open with Excalibur and blinding Mordred as blood from a shallow cut in her forehead leaked into her eyes, allowing Arturia to impale Mordred with the holy spear Rhongomyniad. Mordred, dying, pulled herself up the length of the spear to try and reach Arturia, her helmet breaking to reveal a face identical to her "father" and calling out to him, attempting to touch Arturia once in her lifetime but being denied even that as she fell - but her cursed body struck one final time as she died, finally catching Arturia off-guard at the unexpected strike from her dead opponent, slicing Arturia's body with Clarent's blade and fatally injuring the king.
Dying, Arturia was escorted to a Holy Isle - the Isle of Avalon, sharing the name of her blade's scabbard - by Sir Bedivere, last member the Round Table, with Bedivere expending most of his energy in trying to save her, unwilling to accept that Mordred's dying blow has caused a fatal injury. On the Isle, Arturia was also met with Morgan le Fey, living in exile after having finally abandoned her pursuits of the throne, with Morgan shocked to discover upon examining Arturia's injuries the truth behind Arturia's gender and identity, humbled and mortified to learn that Arturia had been female like her, and thus, hadn't denied Morgan the throne simply because of gender.
Arturia explained she had indeed been Uther's child and rightful heir, and forgave Morgan in her final moments, reconciling with her half sister and leaving Morgan in tears as the mage was filled with shame and regret over what she had done and over the misunderstanding that had spurned her jealousy, which ended up being the destruction of the kingdom. Arturia then ordered a grieving Bedivere to dispose of Excalibur by throwing it back to Vivian. In his absence, Arturia looked back on her life and reflected on her personal failures, ultimately coming to regret her life as king. Before her last breath, she appealed to the world and the counciuousness of humanity - Gaia and Alaya - and pleaded with them that, in exchange for services as a Heroic Spirit, she would ask to be given an opportunity to seek the Holy Grail to save her country from the mistakes of her rule, by re-doing the selection of the king and ensuring she never became the King of Britain.
Arturia is summoned as the Saber-Class Servant of the Fourth Holy Grail War under Emiya Kiritsugu on behalf of Jubstacheit von Einzbern and the Einzbern family, who use her lost scabbard Avalon - found and excavated from Cornwall - as the catalyst for her summons. Kiritsugu, while surprised that Arturia is female, goes to Fuykui and partners Arturia with his wife and the Lesser Grail vessel, Irisviel von Einzbern, to act as her Master in the open while he acts from the shadows with his protege, Hisau Maiya. Arturia never learns of Avalon, which is placed inside Irisviel in order to prolong her shortening life. Due to her unique status as a incarnate soul being projected from her still-alive body hundreds of years in the past rather then a dead Heroic Spirit remade for the war, Arturia is unable to dematerialize, thus she and Irisviel arrive by plane.
Her first fight is with Lancer-Class Servant Darmuid Ua Duibhme, and despite a mostly even fight, she is left with a wound from Gae Buidhe to her left hand that prevents her from using her full strength and Excalibur. The fight is then interrupted by Rider-Class Servant Al-Iskandar, who invites the pair to join his kingship, but Arturia denies as her own kingship is reason to "never bow before another lord." She soon after meets Archer-Class Servant Gilgamesh, who claims his own rule exceeds theirs, and a Berserker-Class Servant who takes an interest in Arturia. Lancer is forced by a Command Spell to help Berserker kill Arturia, but Rider defends her so that they can properly finish their duel later. After this, she and Irisviel meet the deranged Caster-Class Servant Gilles de Rais, who mistakes her for Joan of Arc due to a slight resemblance in their appearances. She drives him off, but is unable to convince him of his mistake.
After Kiritsugu attempts to kill Lancer's master, Kayneth Archibald El-Melloi, to remove the curse on Saber/Arturia's arm left by Lancer, both Kayneth and Caster plan separate attacks on the Einzbern Castle. Saber, discussing strategies with Kiristugu and Irisviel, is disgusted by Kiritsugu's attitude toward the war, and his actions of attacking Kayneth when she had a planned duel with Lancer and his avoiding Caster to let another Servant kill him. Caster then taunts Saber by slaughtering a number of children, and she rushes to meet him - but cannot overcome his Noble Phantasm, Prelati's Spellbook, while her own is sealed. Lancer comes to help her, honor-bound by their promised duel, and together, they force Caster to retreat - however, he leaves soon after after Kiritsugu injures his Master. Saber then saves Irisviel by unknowingly providing the Avalon inside her with energy after Irisviel received a fatal wound from Kotomine Kirei.
Kiritsugu goes out on his own afterword, and Irisviel and Saber are then approached by Rider, who offers a "battle without bloodshed" by inviting them to a talk with Archer. In the meeting, Saber expressed her wish to erase her rule from history and was scorned by both Rider and Archer as being a nieve child who was running from her mistakes and throwing away her pride as a king rather then taking responsibility for her rule. Assassin-Class Servant Hassan-i-Sabah of the "hundred faces" then shows up, who Rider promptly kills while explaining his own ideals of what a king is, shaking Saber to her core as, for the first time, she wonders whether she was wrong about her ways and if it was her ideology that was at fault instead of her.
After this, when Caster goes berserk and attacks the city, Saber works with Lancer, Rider and Archer to kill him in spite of Berserker's interference, with Lancer breaking his Gae Buidhe lance to restore her arm. After the fight, she has her promised duel with Lancer, but to her horror, Kiritsugu intervenes by forcing Lancer's master to order Lancer into committing suicide. Disgusted and shamed by Kiritsugu's actions, she grants Lancer's Master a mercy-kill. Shortly after, Berserker kills Maiya and abducts Irisviel, who is brought to Kotomine and murdered, much to Saber's grief. On the final day of the war, Saber faces off against Berserker, realizing that he knows she is King Arthur after he defends against Excalibur in spite of the blade being invisible. She demands Berserker reveal his identity by calling his honor as a knight into question, and is left shocked and horrified as Berserker replies by drawing Arondight and dispersing his black fog to reveal a hauntingly familiar suit of armor, devastated to learn that Berserker is actually Sir Lancelot, her trusted friend and first Knight of the Round Table.
Rider's words haunt Saber as she fights Berserker, believing that Lancelot becoming a mad warrior stemmed from him hating her. They duel until Berserker exhausts the prana supply of his master, Matou Kariya, and Saber uses the chance to impale him. Saber apologizes to Lancelot in sorrow as she desires to change the past, and that by erasing her time as king, Lancelot would be able to love Guinevere without fear or penalty. Lancelot, regaining his sanity in his last moments, corrects Sabers assumptions by explaining that he had wanted her to punish him for his actions because he was unable to forgive himself for falling in love with the Queen and causing the spark that fed Mordred's rebellion. As he fades away, Saber wanted to say he was a loyal knight, but is unable to find the right words, with Lancelot telling her that Saber was the greatest king and that all those that served her felt the same. As he fades away, Saber resolves to win the Grail so that she can save Lancelot and her people from their fate.
Upon finding the Grail, she encounters Archer, who has slain Rider, waiting for her. He proposes that she become his wife and she refuses, resulting in a short fight where he easily incapacitates her. Refusing to give up as the Grail is right before her, she takes note of Kiritsugu's presence and begs him for the power of the Command Spells in order to defeat Archer - but much to her horror and despair, Kiritsugu uses his last two Command Spells to force her to destroy the Grail, and against her will, she swings Excalibur and destroys the vessel of the Holy Grail. It's content's spill into the earth as she fades away, razing the land permanently and killing almost everyone caught in it's black mud - a sight Saber does not witness, failing away the moment the grail is destroyed as the explosion engulfs her and burns her to death. Unknown to her, Kiritsugu had done this because he realized the Grail was the container for the avatar of All the World's Evils, Angra Mainyu - but Saber never knew this, and died cursing Kiritsugu for his actions.
Saber awakens on the Isle of Avalon as Arturia Pendragon once more, remembering the words of Lancelot and Iskandar, and takes note of Bedevire standing before her, realizing that he is being dishonest about having thrown Excalibur away and ordering him to do so again. Reluctant, he leaves once more, and Arturia repeats her plea to Alaya and Gaia to become a Heroic Spirit once more in order to obtain the Grail. She is then summoned as the Saber-Class Servant of the Fifth Holy Grail War by Emiya Kiritsugu's adoptive son Emiya Shioru, after the boy was pursued home by Lancer-Class Servant Cú Chulainn, who came to finish his job of killing Shirou after Shirou was revived by Tohsaka Rin's pedant. Shirou had been having dreams about Excalibur in the days leading up to the start of the Holy Grail War after receiving his Command Spells due to the Grail having decide that Arturia would indeed return.
Avalon, implanted in Shioru by Kiritsugu to save his live, reacts with Shirou's mana flow and causes the image of a "sword" to manifest in his subconscious. While attempting to escape from Lancer, he stumbles into his Father's shed which contains the traces of the magic circle established by Irisviel during the previous war. With both the circle and the Catalyst - Avalon, inside Shirou - present, Arturia's second summoning is complete. After Saber quickly commences with the formalities of finalizing their contract, she engages Lancer. She manages to keep the upper hand with Invisible Air until he uses Gáe Bolg, but is saved by luck, allowing her to survive with a large wound while figuring out his identity. Lancer withdraws afterword due to orders from is master and Saber heals herself to the best of her ability with the lance's curse affecting the wound. Upon sensing more enemies - Tohsaka Rin and her Archer-Class Servant/Counter-Guardian EMIYA - Saber goes to engage them until Shirou is able to forcibly make her comply, though not before wounding Archer and making Rin to use up her second Command Spell to force Archer into astral mode to keep Saber from wounding him further. Thus, Saber and Rin explain the Grail War to Shirou.
After being taken to register for the war at the Kotomine Church, the group is attacked by Illyasviel von Einzbern and her Berserker-Class Servant Heracles, resulting in Saber being badly injured and Shirou nearly being killed taking a blow that was meant for Saber. Illya, shocked that the boy she held a grudge against for years would save his Servant in such a way, calls Berserker off and leaves. Shirou is brought home to be healed, but the damage Saber received from Berserker doesn't weigh as heavily on his mind as protecting others, including Matou Sakura, his childhood friend. After Saber explains the details of the War's end-goal, Shirou brings up the topic of Illya and the Einzberns, and after contemplating an explanation for Shirou, she reveals that she was Kiritsugu's Servant in the Fourth War, which shocks Shioru.
Saber then decides to direct him to Kotomine Kirei, even though she wishes have as little contact with the priest as possible - but despite that, she firmly believes that Kirei is someone who will answer any questions clearly asked of him. As they head to the church, she suggests Shirou not reveal that she was summoned again for this Grail War, not knowing that Kirei is Lancer's Master and thus already knows. Shirou thus learns from Kotomine that Kiristugu was the Magus Killer who represented and then betrayed the Einzberns to destroy the Grail, and that Kirei was a master who fought and hated Kiritsugu - upon leaving the Church with his answers, Shirou finds Saber's worried reaction funny, and also causes him to wish to reaffirm their contract as allies. However, due to the improper summoning and Shirou's lack of ability to provide prana for Saber, she carries limited reserves of prana and must ration it carefully.
Shirou and Saber decide to patrol at night, giving a false explanation to Taiga and Sakura about why Saber is staying with them. On their first night, Saber senses a Servant, and they find Matou Shinji and his Rider-Class Servant preying upon a woman for energy, with Saber quickly overpowering Rider. Zouken Matou then appears before they can deal with Shinji, and Shirou is appeased with Zouken taking charge of Shinju, though Saber is reluctant to let Shirou near him due to Zouken being inhuman. She stares her hand to help save the woman's life as they bring her to the church for healing, and after Shirou makes a clear resolution to end the war, Saber swears that she will never betray his trust. The following morning, Saber and Shirou argue about sleeping arrangements and whether he should go to school without her with him.
After returning home and clearing up a misunderstanding between Taiga and Saber regarding sleeping arrangements, they go on patrol and plan to check the Ryuudou Temple after getting a tip from Tohsaka Rin about a Master and Servant there. Saber agrees with a direct attack, but the pair find little aside from the abandoned Katana - the last mark of the recently-killed false Assassin-Class Servant Kojirou Sasaki, before it fades away. As they enter the temple, they find Caster-Class Servant Medea standing over the dead body of Kuzuki Souichirou, dazed and covered in blood with her weapon out. Shirou warns of an ominous feeling he gets seeing Caster's dagger, but Saber charges forward in anger after mistakenly assuming Caster murdered her own Master. Caster, angered and put into hysterics by the accusation, attacks Saber but Saber easily negates her spells and cuts Caster down. They contact Kotomine to heal the temple's residents and return home.
The next day, Shirou is left sick due to Rider, still alive, using Breaker Gorgon on him to drain his energy - and possibly rape him - forcing him to stay inside that day. After a strategy meeting with Rin where they shockingly discover Caster's magic hasn't vanished, they patrol with Rin and Archer to find that Matou Zouken has turned Caster's body into a puppet with his worms before her corpse could dissolve with her death. Saber promptly kills the corpse and watches it to ensure Caster dies for good, while Archer bisects Zouken - but before he can try to finish him, a mysterious "Shadow" appears, and after Shirou accidentally steps into the darkness it trails, they are forced to leave with him in tow. When Shirou recovers, he opts to make hunting the Shadow a priority after Archer reveals himself to be a Counter-Guardian and that the Shadow is a danger to humanity. Saber obliges Shirou's wish unflinchingly, though Shirou fears she will see the act as betraying her wish for his own ends like Kiritsugu seemingly did. What Saber does take issue with is Shirou inviting Illya into his home in spite of the little homunculus having tried to kill him.
When night falls, Saber senses the Shadow at the Ryuudou Temple, and leaves with Shirou to face it - however, she splits off from him in order to engage the True Assassin-Class Servant, Hassan-i-Sabah of the "cursed arm." She engages him and easily deflects all his throwing daggers before using a prana-burst strike rom Invisible Air to strike at him - however, much to her shock, she is suddenly restrained by the Shadow, which emerges from the dark and engulfs her feet. True Assassin mocks her by revealing that the only magic he knows is the warding of winds from being a desert spirit, thus her wind-based attacks were useless on him, and that he never planed to fight her so much as simply keep her distracted.
Horrified, Saber tries to free herself by expending all of her scarce prana, but True Assassin reveals his trump card - his Noble Phantasm, the cursed arm Zabanya: Delusional Heartbeat, and attacks her with it while she is trying to escape, succeeding in piercing Saber's chest with the cursed arm. However, Saber manages to cut off True Assassin's arm before it can punch through her body fully and tear her heart out - but the damage is already done, as between the injury to her chest and the depletion of her prana, she no longer has any hope of escaping the Shadow. Collapsing at last and wallowing in her despair at having been tricked so easily, Saber mutters a final mournful apology to Shirou for her failure before the Shadow engulfs her and swallows her whole.
After being swallowed by the Shadow, Arturia fights against it's corruptive influence long and hard, unwilling to let the taint change her or stop her from reaching her goal. However, all that changed when, after days of fighting it, she finally discovered that the same corruption, the same anger and hate and evil she was fighting against, *was* the thing she had desired - the true power that lay inside the Holy Grail. The Shadow was the manifestation of the Holy Grail's tainted contents - Angra Maniyu, the avatar of All the World's Evil. She also learned from the Grail the reason why Kiritsugu had betrayed her in the Fourth War and ordered her to destroy the Grail was because he found out what was inside it and that it would be released the moment somebody made a wish on it - instead of some lofty sense of vanity or unwillingness to use it, Kiritsugu had simply had more information then Arturia did about it. As a result of this corruption, the Grail was incapable of granting a wish - if it ever was capable of it in the first place, for something as immense a desire as rewriting one's entire past may well have been something that not even the untainted Grail could do.
This simple fact - this undeniable truth that the thing she had fought two Grail Wars to obtain could not grant her one wish and reverse her rule as King - broke Arturia, and at long last, the indomitable King of Knights gave into her despair. All of the things she had endured - Her plea and subsequent contract to Alaya for a way to undo her mistake of a kingship. Diarmuid's disgrace before her by Kiritsugu's hand. Killing the insane Lancelot by her own hand. Being beaten by Gilgamesh. Being betrayed by Kiritsugu while on the verge of claiming the Grail and being forced to destroy her "salvation." Being summoned again to a limited master with little prana of her own and trapped in dire straits for days. Being forced to put aside her dream of salvation once again for the ideals of her Master when Shirou decided to face the Shadow. Being drawn in like a fool and humiliated by the True Assassin predicting her thoughts as though she had been a novice warrior. Being swallowed whole by the Shadow in spite of her valiant defense. Fighting the corruption with every fibre of her being for days - all of it flashed before her. And all of it for a worthless prize - the container for All the World's Evils, which could never grant her wish of undoing her time as King. All of her struggles had, ultimately, amounted to nothing.
At that moment, Arturia can be said to have truly "died," in that everything that was the kind-hearted girl that had been Arturia Pendragon ceased to exist upon having her last desperate hope, her final plea to the Heavens for salvation, unceremoniously dashed before her eyes once and for all. In Arturia's own mind, she had regarded herself as having essentially being dead ever since the hill of swords at Camalan, with all her prayers and all her glory vanishing to dust on the day she and Mordred dealt each-other the fatal blow - that she had been dead ever since that day, and that it only took until now for her to finally realize it. Regardless, the effect was the same - the pride of the King of Knights, the last thing she truly had, crumbled away with her hopes and dreams as Arturia gave into complete despair.
She no longer fought against the corruption of Angra Maniyu, for she had no reason to try anymore - her desire to fight, the reason she had pleaded with Alaya to make her a spirit that could bring about her one wish, was gone - thus she became blackened and her nature inverted. Skin paled, hair bleached, armor was stained black, red veins crept across her body. Her eyes became glinting golden jewels that burned endlessly, forever losing their calming kindness, and the holy blade that once embodied the power of mankind's hopes and dreams became an ebony-black sword that fed off the despair of broken hopes and dead dreams and the anguish of those that suffered from such loss. In the end, what emerged from the black mud of the tainted Grail was no longer the King of Camelot - instead, what rose up from the darkness was a creature bound to a world she no longer cared about, swinging her sword without concern, without passion, and without mercy, as it was all she had left for her existence. Thus, the Black Saber, "Saber Alter," was born.
With the Grail itself fueling her with infinite prana, Saber Alter was physically stronger then she was in life, allowing her to overpower even Heracles with her blade when she returned alongside the Shadow and True Assassin, no longer restrained in her use of Excalibur and able to use it as much as she wished. Due to the grail, she had gained an incarnate body of flesh and blood - however, it was an ironic reward, in that she had been given a body when she no longer had any reason to live nor a desire to find a new reason. She faced off against Archer briefly before retreating into the Shadow, and returned to escort the corrupted Sakura after the later was overtaken by the Shadow's influence, chastising Shirou for "foolishly" hoping he could save Sakura. She later on is sent to kill Shirou, but after he kills the blackened Berserker, Saber Alter decides to spare him, dispassionately explaining that he earned the right to live another day in killing Berserker.
But, utimately, in spite of her power, at the end of the War she was ultimately defeated by the Rider-Class Servant Medusa and Emiya Shirou. After allowing Rin to pass into the Grail cavern on Sakura's orders, she faced off against Rider, weakened by her Mystic Eyes of Petrification but immune to being turned to stone, repelling Rider's attacks at every turn. However, her lack of passion or sense of urgency and desire in the fight was what undid her in spite of supposedly being invincible, as Rider succeeded in ensnaring Saber Alter's legs with her chains, distracting her long enough for Rider to leap back and prepare her Noble Phantasm, forcing Saber Alter to ready her own. Rider and Shirou then worked together using Bellerophon and Rho Aias to break Saber Alter's Noble Phantasm, Black Excalibur - and in breaking her holy sword, destroy the very last thing Arturia had to her name in the Grail War - before Shirou remorsefullly killed her himself, straddling her and sabbing her through the heart with an Azoth Dagger he received from Rin, slaying her incarnate body as he gave her a final thank you for having saved his life before. Shirou then went on to free Sakura, before being saved from his self-destructive death by Illyasviel von Einzbern, who gave Shirou a new body to live in and sealed the Holy Grail.
After her demise in the Grail War, Arturia was returned to her own time, reawakening just before her final death in the legends, and, living her last moments without joy or sorrow, dispassionately ordered Bedivere to throw Excalibur back to Vivian the Lady of the Lake. Broken and listless from her final battles, she retained the mantle of emotionless king right to the very end as she had no means to alter what she had done, and thus lost all will to care. Upon her final death, her contract to Alaya broke and she was made a "true" Heroic Spirit and recorded into the Throne of Heroes - but, due to the nature of her contract, she went to the throne with her memories of the Grail Wars intact, which was typically only done for Counter-Guardians. As such, Arturia was tainted by her encounters and would remain in the Throne as the dispassionate being she died as in the Fifth Grail War, with her despair-tainted heart barring her from going to the paradise of Avalon upon her death.