"Kingslayer" is a song by British rock band Bring Me the Horizon and Japanese kawaii metal band Babymetal. 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. Despite not being released as a single, the song has become a commercial success, charting at no. 51 on the UK Singles Chart and receiving sales certifications in several countries. Oliver Sykes described the song as "sound[ing] like an anime TV trailer." 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. He used this idea as an analogy for then US president Donald Trump calling Antifa a "terrorist organization" and the chaos caused by the Extinction Rebellion, with Sykes feeling that people have to go out and do what they feel is right, no matter the cost. Hence the themes and for "Kingslayer" to break the barriers of the reality. 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". Babymetal originally recorded all of their parts in English before Sykes asked them to re-record in Japanese.