Pasi Koskinen is a Finnish metal vocalist best known for his work with the band Amorphis from 1996 to 2004. He is currently the vocalist for four active bands: Shape of Despair, Mannhai, Ajattara (under the alias I. Ruoja Suruntuoja), and To Separate the Flesh from the Bones (under the alias Herr Arschstein). He was a founding member of Shape of Despair, and was married to the band's other singer, Natalie Koskinen.