Krupp was a menial working for the Fatui, one of Dottore's adjutants and a character original to the Genshin Impact manga.
He first appeared in the Haeresys, a Fatui underground arena where captured test subjects are used to fight an unknown creature. Displeased by his menial, Dottore calls his work "pathetic as usual" before threatening Krupp to become one of his test subjects instead.