Usagi: The Black Samurai

Usagi Tsukino, also known as Sailor Moon, was visited by a person who wanted to change Usagi's destiny. Usagi agreed as she was told how her life was going to go if she didn't, being reborn as a past relative, The black samurai, she got to choose how she looks.

Being reincarnated as a child around the age of ten with memories of sword techniques and who she was in that world, not knowing she was in fact the black samurai. Serving under the women who found her, Nobunaga, until she died which forced Usagi to become a Ronin, at the age of 11.

She is soon taken in by another women by the name of Miyamoto Musashi, taking the last name Miyamoto. Though it doesn't last long, as Usagi falls during battle at the age of 17, which hurts her mother figure, Musashi.

Though she instead gets sent to the Holy Grail, soon being summoned during a time of peace, as their was no grail war or anything dangerous going on by her summoner, Olga Marie. Learning that she is a assassin class, and reunites her old sensei, Nobunaga, and her mother figure, Musashi, but... why are they glaring at each other so much?

How will the other servants react to Usagi? How are the Sailor Guardians doing without their old sailor moon? Why is there barely anything else known about Usagi's story?