Produced by Bring Me the Horizon's lead vocalist Oliver Sykes and keyboardist Jordan Fish, the song appears on the group's 2020 commercial release Post Human: Survival Horror.
"[1] Sykes initially came up for the idea of the song while he was playing Call of Duty in Amsterdam, with the Kingslayer being what everyone wants to be.
Sykes would go on to compare the sound of the song to something off their second studio album Suicide Season, and how the cute vocals of Babymetal on the chorus would make for a perfect contrast on "Kingslayer".
[2] Babymetal originally recorded all of their parts in English before Sykes asked them to re-record in Japanese.
A live music video was released for "Kingslayer" composed of footage from the Tokyo performance on 14 December 2023.