Øystein Garnes Brun (born 14 April 1975) is the guitarist and founder of the Norwegian heavy metal band Borknagar.

Brun gathered a cast of musicians who were well known in the black metal scene including Infernus of Gorgoroth, Erik Brødreskift of Immortal and Gorgoroth, Ivar Bjørnson of Enslaved, and Kristoffer Rygg of Ulver, Head Control System, and Arcturus.

The stature of these musicians caused Malicious Records to award the band with a contract without even hearing them.

[2] Through the years, the personnel has changed, but the sound is influenced mainly by Brun, so the style of music has been consistent despite a revolving lineup.

Their debut album Terra was produced by Dan Swanö and released in 2006 on Century Media.