Heriot promoted the album with performances at several European festivals in June 2024, before touring with Sylosis and Fit for an Autopsy in November and December that year.

According to Mia Hughes of Stereogum, the EP turned Heriot into "one of the [UK's] most hyped heavy exports",[1] and the band's debut album was highly anticipated.

[8] Guitarist Erhan Alman said although Heriot felt pressure to live up to their hype whilst writing the album, it "became secondary to making something that we thought was wicked.

[10] In March 2023, Heriot wrote the "first iteration" of Devoured by the Mouth of Hell and mid-year they toured Europe and performed at various festivals,[1][2] including 2000trees, Damnation, Slam Dunk and Standon Calling.

[14] Drummer Julian Gage said that the band had not considered how their songs would work in live settings when they conceived the EP, amidst the COVID-19 pandemic.

[2] Gough said Middleton emphasized "how we [needed] to have bits to come back to that will stick with people live" during recording,[16] whilst Alman said he told the band to write riffs that would attract the attention of a bystander if they were performing at a festival.

[20][21] Middleton and Jake Packer, the band's bassist and vocalist, co-produced the album,[22] whilst Justin Hill of Sikth helped engineer Gage's drum tracks.

[2] Packer spent weeks making notes about the album's tracklist, before reaching an agreed "final iteration" with Alman and Gough.

[30][35] Matt Young of The Line of Best Fit highlighted the "dual vocal dynamic" between both members as "a key feature of Heriot's sound, giving their music an unsettling, multifaceted edge".

[2][13][15] The band cited artists including Billie Eilish,[36] Korn,[36] Slayer,[36] Slipknot,[36] and Sophie[13][29] as influences on the album's sound and direction.

[36] Gough cited Wand, specifically their second album Golem (2015), as a "huge source of inspiration in aiming to capture depth within our clean sections".

[29] "Foul Void" and "Siege Lord" rely on heavy riffing;[30][34] the former song was influenced by 1990s-and-2000s-era metalcore,[37] and was considered by Gough and Packer to be a "blueprint" for the album's direction.

[32] On "Opaline" and "Visage", Heriot expand on their shoegaze and electronica influences;[33] both songs also contain elements of ambient music and progressive rock.

[34] "Lashed" drew influence from the works of Sophie and Sara Landry,[13][29] and was considered by Gage to be a "natural progression" from Profound Morality's electronic material.

[25] In an interview with Dork, Gough said the phrase "mouth of hell" in the album's title is intended to represent the "overarching idea of being completely consumed by something", though it can also relate to "everyday living, existentialism, poverty, class, [and] internal grief".

[49] The video for "Foul Void" was filmed inside a former-college-turned-property guardianship where Gough lived near Walsall, where Heriot spent six weeks working on Devoured by the Mouth of Hell.

[54] In April 2025, Heriot are due to begin a short headlining tour of the UK,[55] supported by Grove Street and False Reality.

[8] In a 5/5 review for Kerrang!, Nick Ruskell called Devoured by the Mouth of Hell a "perfect document of [Heriot's] powers", praising the band's improved songwriting and atmospherics.

[34] According to Andrew Sacher of BrooklynVegan, the album successfully balances melody and brutality without compromise; he also highlighted the vocal performances of Packer and Gough.

[31] Daanii Lievers of Metal Hammer considered the album the "confident work of a far more experienced band" and praised Heriot for "seamlessly sewing together textures and tones and creating full tracks from surprising influences" without being "disjointed".