He further calls the track a "heaven/hell juxtaposition" that "feels like the most logical step imaginable for Sigur Rós in light of last year's Valtari, a Calgon bath of a record that suggested that the band had run out of ideas.

Yet somewhere in the darkness, Sigur Rós sprinkle rays of light amongst the orchestral storm and the song is propelled to all new heights through the falsetto vocals of Jónsi Birgisson and accompanying strings.

This is easily Sigur Ros’ heaviest track to date, nodding to the bleakness of ( ), yet treading new territory for the real second coming of the newly downsized three-piece".

He further complimented the band by saying "If this is any indication of the newly downsized three-piece’s new direction, Sigur Rós fans are in for a treat and true return to form.

[8] "Brennisteinn" was first used in commercial media in the E3 trailer for Ubisoft Montreal's critically acclaimed 2013 video game, Assassin's Creed IV: Black Flag.

The track was used in a commercial for Alien fragrance by French fashion brand Thierry Mugler which portrayed the awakening of Sun Goddess.

All tracks are written by Jón Þór Birgisson, Orri Páll Dýrason, Georg HólmAdapted from Kveikur liner notes.