child assassin (fate/zero)
One of the various split personalities of Fate/Zero's Assassin, cut from the final version of the novel. She world later receive canonical appearance in Fate/Grand Order's story mode.
In the original draft she infiltrated Gilles de rais (caster)'s lair and was taken in by Waver Velvet and Iskandar. She would eventually regain her memories through one of Kotomine's command spells and Waver would be forced to kill her.
This tag implicates assassin_(fate/zero) (learn more).