Saber Alter, also known as Dark Saber, is a villainess from the Fate series. She is the dark, evil version of the proud, idealistic servant Saber. She is voiced by the same seiyuu that voices Saber herself, Kawasumi Ayako.
Saber Alter makes several appearances in both the Fate series and Carnival Phantasm; in the Heaven's Feel route, Saber becomes corrupted by the darkness by Angra Mainyu and becomes Dark Sakura's servant, Saber Alter. Saber Alter abandons the ideals that the original Saber had, which easily disgusts Gilgamesh as he prefers the more idealistic Saber when she was resisting him. She also appears in Fate/kaleid liner PRISMA☆ILLYA, but a black face mask covers her eyes as a class card.
In Carnival Phantasm, she has several cameos in Episode 7 as both a figure and a figma, and in Episode 8, Saber becomes so angry and frustrated with Gilgamesh that she transforms into Saber Alter, whose darkness instantly attracts the men eating at Ahnenerbe, including Gilgamesh. She later reverts back to her old self as standard Saber when she comes back home to Shirou from work.
It was estated that Saber Alter isn't a true villain, but rather a dark heroine.
Saber Alter is a negative palette swap of Saber. Her skin and hair are even more pale, and her dress is black while her armor is darkened and becomes dark purple, with several blood-red linings painted on it. She carries a black sword with blood-red linings and has yellow eyes.
For casual clothes, she wears black gothic lolita fashion, and in Carnival Phantasm, while working as a waitress, she wears a black version of Saber's waitress outfit.
- Both Saber Alter and Dark Tohka corrupted version of the hero with armored dresses and both are monarchs and control the power of darkness.