She is a half-demon and has been alone for as long as she can remember. Inadvertently, she discovered that she could change her state at will, becoming a human or a monster.
Then, she began to adapt to modern human life. She didn't even remember how old she was now, and her life was like fresh water.
It was not until later that she met Kagome and was adopted by the Higurashi family that her life gradually became interesting.
One day, she accidentally fell into the dry well of Higurashi Shrine and came to the Warring States Period. Kagome also traveled through time because she was looking for her.
See how her modern half-demon plays with the Warring States Period!