Fenriz created Isengard because he had many musical ideas that didn't fit in with the style and music of Darkthrone.

Fenriz performed all instruments and vocals himself.

Vinterskugge is a compilation of three demos recorded before Høstmørke full length album was recorded.

When asked how he felt about Isengard in a November 2007 interview, Fenriz commented that he doesn't "understand why people like it so much". He stated that people like "the elements" which he doesn't like, namely the project's folk metal aspect.

(source: Wikipedia)