Produced by frontman Oli Sykes, Zakk Cervini and DaiDai, it was released as the fifth single from their seventh studio album, Post Human: Nex Gen on 13 October 2023.

[3] On 9 October 2023, the band sent an email to fans on their mailing list about a newly titled song "Darkside", alongside some lyrics "Think my angels fallen" as well as the release date.

[4] The band kept teasing the song on social media, posting snippets on Discord and TikTok, until they released "Darkside" on 13 October.

Eli Enis of Revolver stated, "Its chorus is absolutely anthemic, while the verses have bouncy nu-metal riffs and a delivery from Sykes that evokes Linkin Park.

He remarked, "Vocalist Oli Sykes utilises his fundamental screams and singing throughout the catchy chorus and quieter verses as the band masterfully infuses their blend of electronic influences alongside nifty drum beats and ramping guitars.