Multiple outside songwriters assisted with the album, including pop producers Salem Al Fakir and Vincent Pontare, Kent lead singer Joakim Berg and The Cardigans guitarist Peter Svensson.

In a 2021 interview with radio station KLAQ, frontman Tobias Forge stated that he came up with the concept of Impera in 2013 after reading the book The Rule of Empires: Those Who Built Them, Those Who Endured Them, and Why They Always Fall by Timothy Parsons.

The band then entered the studio in January 2020 to begin working on their fifth album, and planned to release it by late summer that year.

[4] In March 2020, during their final show supporting their 2018 album Prequelle in Mexico City, Cardinal Copia, the singer of the band, was transformed into Papa Emeritus IV.

On 30 September 2021, the band released a single, "Hunter's Moon" for the 2021 slasher film Halloween Kills with a different version of the song being played in the closing credits.

[21] The album's sound has been described as 1980s-style pop and rock[22] and has been compared to ABBA, Boston, Dio, Bon Jovi, and Def Leppard.

[2][11] It is described to take place hundreds of years forward from the 14th century Europe Black Plague era of Ghost's previous album, Prequelle.

[12][24] During the first show in Reno, the band performed "Kaisarion", the second song of the album, for the first time,[25] as well as introduced new steampunk-inspired costumes for the Nameless Ghouls.

[34] Thom Jurek of AllMusic was positive towards the album stating, "Impera is the most unabashed exercise in exultant pop/rock sheen Ghost has issued to date; it establishes an exquisite front in their own quest for global rock domination.

"[35] According to Mark Beaumont of Classic Rock, "Ghost swap Medieval demons for modern-day counterparts..." and compared the album to Green Day's American Idiot.

"[18] The single "Call Me Little Sunshine" received a nomination for Best Metal Performance at the 65th Annual Grammy Awards, but lost to "Degradation Rules" by Ozzy Osbourne and Tony Iommi.