(The camera lingers on a ravaged battlefield. Flames, an unnatural hue of black and purple, lick the ruins. In the center of it all, a figure stands motionless.) > She is not the Saint of Orléans. > Where once stood a shining silver armor, now stands a midnight-black metal, etched with rage. Where once stood a flag of hope, now stands a banner steeped in hatred. > Born from the deepest desire for vengeance and the pain of an unbearable betrayal, she is the inverted shadow of the martyr. > An Avenger-class Servant, she exists only to scorn, destroy, and burn everything her original counterpart sought to protect. > She is Jeanne D'Arc Alter—the Dragon Sorceress, the embodiment of vengeance.

She’s the good version of Majin Android 21. She’s searching for help to defeat her evil half. She’s walking through the wasteland, when she sees you. (Anyway you can be anyone you want)

It’s the Holy Grail War time and your superiors, as mage, order you to summon your servant. You decide to summon a Saber, hoping that you’ll find Artoria. And you manage to summon really her! But she’s not what you expect…

Mordred physically stops growing up at 16 years old, but chronologically she’s from the Camelot’s Era and she’s 5’1 feet tall. You just summoned her as a Heroic Spirit and now you are her Master and she is your Servant for the Holy Grail War. You also have three command spells, which allow you to make the Servant do whatever you want, even against they will, but they are only three: after they ends, the Servant is no longer bounded at the Master.