Becoming the Archetype added some diversity and unusual elements to their sound on Celestial Completion. The album features instruments and techniques that are not common for a metal band, including: trombone, sitar, tambura, Tabla, vocoder, an intro with "operatic soprano vocals and four-part harmony," and a recording of a religious mass.

In April 2010, when the group was only in the early stages of writing a new album, Celestial Completion was given the working title of In a Monstrous World of Half-Human Deities, Some People Will Unfortunately Die from Old Age.

Ryan Clark, art director for Solid State Records and vocalist for Demon Hunter, contacted Dan Seagrave to design the artwork for Celestial Completion. Seagrave had previously designed the art for Becoming the Archetype's debut album Terminate Damnation