Sweden’s Amon Amarth have always adhered to that timeless adage, “if it ain’t broke, don’t fix it.” Their double-time rhythms, guttural vocals and thick, churning guitars are stable, albeit predictable. However, maintaining the thick, growling verses and intense choruses of their previous work yet twisting the formula by inviting a few like-minded collaborators into their recording sessions keeps the band invigorated. The inclusion of Entombed vocalist L.G. Petrov, Children Of Bodom guitarist Roope Latvala and string quartet Apocalyptica breathe new life into Amon Amarth’s sound, as on the churning bombast of “Guardians of Asgaard,” the title track and “Live For The Kill,” respectively. While reinventing the Death/Viking-metal wheel isn’t exactly their forté, as Twilight of the Thunder God proves, a touch of innovation can go a long way.