|Appears in:||Fate/Grand Order|
|Japanese VA:||Ayako Kawasumi|
|Character type:||Servant (Master: Protagonist)|
|Place of Origin:||Britian, England|
“The Artoria Species is like a cancer of the universe.
Someone must reap them out.
—Mysterious Heroine X
Assassin's True Name is Mysterious Heroine X (謎のヒロインX, Nazo no Hiroin?), also known as Heroine X (ヒロインX, Hiroin X?) and just X, an unknown heroine who tasked herself in eliminating Saber-class heroines during Back Alley Satsuki - Chapter Heroine Sanctuary. Bearing the code name "A-X", X was a stranger who came from the "mysterious dimension" called the Servant Universe (サーヴァントユニヴァース, Sāvanto Yunivāsu?). Seeking to accomplish her "true, dearest wish" to "defeat all Sabers", she brandished Secretcalibur and left her home town, leaving behind an "expression full of bitterness." Even before arriving at Chaldea, she managed to save an ancient royal dynasty from a crisis, settle the internal strife of the "Mankind Integration Union", and rout invaders from another universe, but such actions were trivial enough for her to not even remember accomplishing them. She will continue to brandish her sword until her goal is completed, and can still be seen "dashing across the sea of stars" even today. No matter what, she also plans to cut down the "Golden Great Emperor Cosmo Gilgamesh."
X has revealed to none that her true identity is actually Artoria Pendragon. While she believes that her "perfect disguise" has tricked everyone, it is asked that others keep the fact quiet to keep from spoiling it and also for the sake of X's own honor.
“It's sticking out...it's sticking out...it's really sticking out.”
—Assassin's profile, on her ahoge
Assassin's appearance is said to be composed of "rough and sporty garments unseemly for Servants." Her blue muffler is a symbol of courage, and her cap is used to hide her identity and ahoge, although it sticks out of the cap.
Mystery Heroine X's wish for the grail is the destruction of all other sabers. Or at least for them to change their class name to Attacker or Swordsman or something.
Assassin claims to be the "definitive edition of the Saber Class", acting as an Anti-Saber Decisive Weapon (対セイバー決戦兵器, Tai-Seibā Kessen Heiki?) that "fairly and squarely performs surprise attacks as a knight." She brandishes the "mysterious magic sword" Secretcalibur to massacre her enemies and uses her favorite ship, the Dun Stallion II (ドゥ・スタリオンⅡ, Du Sutarion II?), to travel through space.
Ultra Heroine ZEdit
Ultra Heroine Z (ウルトラヒロインZ, Urutora Hiroin Z?) is an alternate version of Mysterious Heroine X who acts as the antagonist of the "Saber Wars" event.
Creation and ConceptionEdit
BUNBUN is the character illustrator for Assassin.