Isengard was a solo project created in the early 1990s by Fenriz, a prominent figure in the Norwegian black metal scene and better known as one half of the influential band Darkthrone. Named after the fortress in J.R.R. Tolkien's Middle-earth, the music of Isengard is a fusion of black metal, Viking metal, and folk influences, showcasing Fenriz's multifaceted musical interests beyond the primal black metal for which Darkthrone is known. Although conceived during a time when black metal was rapidly evolving, Isengard remained a side project, with Fenriz using it to explore more personal and introspective themes.

The works of Isengard are characterized by their raw production and the integration of Norse mythology and nature into the thematic and lyrical fabric. "Høstmørke," released in 1995, stands as Isengard's seminal full-length album, embracing a lo-fi aesthetic combined with ferocious riffs, experimental folk elements, and atmospheric interludes. After a long period of dormancy, archival releases have brought renewed attention to the project. "Vinterskugge" (1994), a compilation of earlier recordings, and "Vårjevndøgn" (2020), which features previously unreleased material, offer a window into the creative process of one of black metal’s most enigmatic figures and reaffirm Isengard’s cult status within the genre.