Saber Alter of Fate/Hollow Ataraxia

Saber Alter is the Saber-class Servant of Sakura Matou in the Fifth Holy Grail War of Fate/stay night's' Heaven's Feel route. She is a changed version of Saber after being consumed and blackened by the mud from the Shadow. She is one of the Servants of the Protagonist of the Grand Order conflicts of Fate/Grand Order as both Saber and a Rider-class Servant with Santa attributes.

Saber's identity is Artoria Pendragon, better known as Arthur Pendragon and King Arthur.

Corrupted by Angra Mainyu, she is vastly different from her normal self. She is also called Black Saber. In Fate/hollow ataraxia, she wears her casual clothes; a gothic dress called Alter Gothic Dress.

Saber Alter's personality changes vastly from her normal self upon being corrupted by Angra Mainyu, but she cannot be called a villain. She is more of a dark hero who is still an idealist clinging to her own values even after being blackened. After taking in the hatred of the curse, she comes to the realization that the duty of a hero is to be hated and ostracized, that a hero's only duty is to cut down foes using all their strength. She believes that she was prepared for such an outcome upon drawing Caliburn, and decides to entrust her blade to All the World's Evils. While she still takes her duty as king seriously, believing it is her obligation to those whose lives were lost because of her, she no longer believes in the ideals set for herself and her people. The end was concluded long ago, after all her prayers and glory vanished on the hill in Camlann.

In the Heaven's Feel route, the first three days are the same as the Fate route, but the damage Saber receives from Berserker does not weigh heavily on Shirou's mind. After Saber gives her explanation of the basics of the Holy Grail War, the topic of Illya and the Einzberns is brought up. Saber contemplates on explaining due to Shirou's confusion over Illya's hostility, instead telling Shirou to seek out the answers from Kotomine Kirei even though she wishes to have little contact with the priest. This line of conversation leads to the revelation of her connection to Kiritsugu in the previous war and her reason for disliking Kirei as a former enemy Master. Despite her dislike, she firmly believes Kirei is someone who will answer any questions clearly asked of him. As they head of the church, she suggests that Shirou not reveal the same Servant was summoned twice. After he comes back out after learning the answers, Shirou finds Saber's worried reaction funny, and also causes him to wish to reaffirm their contract as allies.