Black String of Fate - Chapter 1: Demon King/Xavier (Prologue)

I originally thought this was a world like an ordinary urban novel…Drawing comics by myself, traveling is pretty good.
But tell me, what happened to this magician called “Emiya Kiritsugu” who jumped on my face?
Who changed the settings?
Currently involved in the content of “F/Z”, “F/SN”, “Fantasy Carnival”, “The Emiya’s Meal”, “The Holy Grail of the Imperial Capital”, “FLA”, “Elmello II Event Book”, “FGO”, “FE”, etc.
Others related to “JOJO’s Bizarre Adventure”, “Rebellious Lelouch”, “Persona 5”, “Attack on Giant”, “Death”
“FGO”, “FE Series”, “FA”, “FSF”, “Cangyin”, “Magical Girl Illya” will be involved next…

- Description from novelbuddy

This is the story of a person who transmigrated into a world with a radically different worldview.

Julietta, born as an illegitimate child of a nobility, is raised in an opera theatre to hide away from the eyes of the noble’s main wife.

She is a top-class spy, a poison specialist, but also a young and cute girl with a sinister temperament. In spite of her sweet and innocent appearance, she can complete any tasks without the slightest hesitation. One day because of an incomplete black magic, she was sent into the body of a girl who was deemed as a good-for-nothing. What kind of change will she bring to this continent?