Vegard Sverre Tveitan (born 10 October 1975), better known as Ihsahn (), is a Norwegian multi-instrumentalist, vocalist and composer, best known for his work with black metal band Emperor. Tveitan is also a founding member of Thou Shalt Suffer, where he played guitar and keyboard in addition to vocal duties, and Peccatum, a project in collaboration with his wife and fellow musician Heidi Solberg Tveitan, also known as Starofash. Since 2006, Tveitan has primarily devoted himself to solo albums and occasional guest appearances.
Beyond the characteristics typically associated with metal music, Tveitan’s musical style also includes classical, industrial, and progressive elements. He is a progenitor of the symphonic black metal genre. Emperor’s final album, Prometheus: The Discipline of Fire & Demise, composed by Ihsahn, epitomizes the genre.