In his book Mean Deviation: Four Decades of Progressive Heavy Metal, Jeff Wagner wrote that Grand Declaration of War features "a variety of vocal shadings to match the multi-layered music", between "A Time to Die", described by Wagner as "one minute and forty-eight seconds of black calculus", "A Bloodsword and a Colder Sun" offering "squishy electronic groove, so close to trip-hop that it instantly became the album's most controversial track" and the "mesmerizing ten-minute sprawling landscape of doom" "Completion in Science of Agony". The album's "sonic clarity" was "a complete 180-degree turn" from the band's early "scuzzy 'necro' approach".^[1] Parts of the black metal scene had hoped Mayhem would not reform after the murder of the original guitarist Øystein "Euronymous" Aarseth as "that would not be right",^[6] or at least were "rather sceptical when it was known that [sic] MAYHEM should go on even without Dead or Euronymous".^[7] Many longtime Mayhem fans despised Blasphemer because "he wasn't Aarseth".^[1] Jeff Wagner calls Grand Declaration of War "Mayhem's own Into the Pandemonium, an album that had perverted and turned inside out the black metal genre as Celtic Frost's [Into the] Pandemonium had done to thrash metal".^[1] Alex Henderson of AllMusic stated that the band "has outdone itself with the epic Grand Declaration of War, which could arguably be described as black metal's equivalent of Queensryche's Operation: Mindcrime".^[2]

A remastered version of the album was released in December 2018; the original 'cold', 'sterile' production was swapped out for a more raw sound with the bass and drums made more prominent in the mix.

AllMusic critic Alex Henderson wrote: "Grand Declaration of War won't appeal to anyone with a short attention span, but for those who can sit down and really give this CD their undivided attention, the rewards are great."^[2]

• Maniac – vocals
• Blasphemer – guitars
• Hellhammer – drums
• Necrobutcher – bass

Technical

• Recorded in Nov/Jan 1999/2000 at Fagerborg Studio and Top Room Studio
• Engineered by Børge Finstad
• Produced by Mayhem and Børge Finstad
• Mastered at Masterhuset by Morten Lund
• Musical Architecture by Blasphemer
• All lyrics assembled, designed and directed by Maniac

Credits

• Anders Odden – co-writing and programming of "A Bloodsword and a Colder Sun"
• Øyvind Hægeland – additional vocals on "Completion in Science of Agony"
• Tore Ylwizaker – samples and noise construction on "Completion in Science of Agony"

Artwork

• Sebastian Ludvigsen – photography
• Mark Francombe Red – cover design
• Anne Cecilie Olavesen – makeup