In late 2001, Fischer and Ain began to write music together again, along with Unala on guitar and, from late 2002, experienced Swiss drummer Franco Sesa (also known within the group under the stage name Inverted Cross). The aim was to develop and record a new, very dark and heavy album. The completion of the project took far longer than anticipated (in part due to the DIY nature of the project and the project's financing) but finally resulted, in late 2005, in what Fischer and Ain describe as "perhaps the darkest album Celtic Frost have ever recorded", based on a combination of the musical aura of "To Mega Therion" and "Into the Pandemonium".