Scaramouche is a prototype puppet created by Raiden Ei. She set him free and an organization called the Fatui took him in.
He helps the Fatui sow conflict between the Shogunate and the Watatsumi Army. He serves as the climactic boss battle in the form of Shouki no Kami, an artificial god. Following his defeat, he falls into a comatose state and is hidden away by Lesser Lord Kusanali.
After recovering and learning that Dottore was responsible for the Tatarasuna incident which was a tramuatizing incident for him, Scaramouche erases all information of his entire existence.