Assassin's True Name is Charlotte Corday (シャルロット･コルデー, Sharurotto Korudē?). Charlotte Corday is the woman that assassinated the leader of the Jacobin faction in the French Revolution, Jean-Paul Marat.
The motive why she reached the conclusion of assassinating Jean-Paul Marat is quite complicated, but if it had to be said in few words, she'd say it was "to save thousands of people". Marat, who agitated the masses, and kept shedding blood for the revolution's sake, was seen as the ringleader of the chaotic France at the moment. Originally, it was a reckless plan that shouldn't succeed. But situations of fortuity/luck/contempt sided with her, and she eventually fulfilled the assassination.
It was later investigated whether there were collaborators in her assassination planning, but the, that it was concluded that there was almost no doubt that Charlotte Corday planned the assassination alone. She was executed with the guillotine, and the man in charge at the moment was Charles-Henri Sanson. In the way from the prison to the execution stage, Sanson traveled with her for about two hours, and admired her in his memoirs with "She kept a gentle and brave attitude to the end, and didn't expose fear or anger".
Due to her beautiful appearance, and her reputation for the skill to plan and execute an assassination on her own, she was praised as "The Angel of Assassination".
A cheerful, precocious, and active but humble girl. Her hobby is reading, and if nothing had happened she would have ended her life at a convent, and her name wouldn't have remained in history. However, due to the convent closing in the aftermath of the French Revolution, her fate changed.
Charlotte is summoned to act as a servant for the Odysseus native to the Lostbelt. He has her enhanced with the Zeus Klironomia, granting her additional combat skills. At some point, he dispatches her to infiltrate Fujimaru Ritsuka’s party, and assassinate them. However, after meeting with Fujimaru and being enchanted by their personality, she is conflicted, and retreats from their presence. After they learn of her true situation, they aid her in removing the Zeus Klironomia, before she receives the Athena Klironomia. The latter allows for the use of a free, additional skill, which Charlotte uses as Battle Continuation. She attempts to ambush Odysseus, but he was on guard after noticing her absence, and gravely injured her. Her newly-granted Battle Continuation allows her to fatally wound Odysseus in turn, but at the cost of losing all memory of Fujimaru. She slowly fades away after professing her love to them, even as she forgets doing so.
Her weapon appears to be a bayonet modified as a knife. The mysterious living being(?) that accompanies her is called an "angel" by Charlotte, but it can't be determined if it's an angel or not. Or rather, it can't even be determined if it's a living being or not.
Angel of Assassination: The namesake people have given her after her death, praising her for her looks and skillful planning in her assassination. She goes with the flow of luck and reduces the wariness of all people she meets or is around her.
Determination of Steel: A Skill granted from her disposition to assassinate based on her decision, despite having no connection to the revolution or assassinations. While nothing as severe as Dantès', she also possesses the Skills combined effects of "Bravery" and "Calm and Collected", granting her resistance to mental interference as well as blocking off her sense of pain and boosting the damage she inflicts in melee combat while also keeping her composure no matter what circumstance she's in.
Ludicrous Planning: A Skill named after the very assassination plan she created and executed on her own , a very thoughtless plan that was only successful due to the various circumstances of luck and other factors on her side that allowed her to achieve this. Though a D+ Rank skill, it can rise up to B Rank when combined with her Angel of Assassination skill.
Charlotte has Klironomia nanomachines, specifically Zeus Klironomia. Due to her Klironomia nanomachines, she is granted the ability to heal themselves and increase their capabilities in combat, as well as a resistance to diseases. She is capable of transforming her body into metal and emitted electricity when her nanomachines went berserk. Charlotte gained an ability to not die by fatal injuries as long as her mission is accomplished from her Klironomia nanomachines. She also has an aura of bloodlust with Zeus Klironomia.
Her Zeus Klironomia allowed her to defeat Cerberus who was also modified by Klironomia.