Inferus is a Brazilian black metal band originally formed in Fortaleza and later based in Recife, with roots dating back to the mid-1990s and a reactivation around 2017. The band channels themes of Satanism, occultism, and darkness, and released the full-length Cult to the Lord of the Evil Light in 2003, recorded at Oficina Studio in Recife. A later release, Paganus Ancestral — Uma Epopéia Pagã, appeared through Black Hearts Records, marking their continued activity into the modern era.

Infestatio is a thrash metal quartet from Jundiaí, São Paulo, Brazil, featuring Rafael "Rafão" Neves on guitars and vocals, Reginaldo "Regi" Iobbi on guitars, Diego "Negão" Necromancer on bass, and André "Fanta" on drums. The band blends old-school and modern thrash approaches with groove-driven riffs and semi-aggressive vocals that draw comparisons to acts like Sadus. Their EP F.Y.A., a five-track release produced by Rafão and recorded partly at Jardim Elétrico Studios, drew favorable coverage from Brazilian metal press on its release.

Infested Co is a melodic death/groove metal band from Bogotá, Colombia, active since 2009. The band released their debut EP Treason Walls in 2014, a six-track record that blends melodic death metal riffing with groove-driven heaviness and lyrics touching on themes of hate and violence.

Infierno is a black metal band from San Salvador de Jujuy, Argentina, with roots going back to 1989 under the name Delirio Infernal before reactivating under the current name in 2013. The band is one of the oldest extreme metal acts from the northwestern Argentine province of Jujuy, and released the rehearsal recording "Ensayo 99" in 1999. Their themes span destruction, hatred, and Satanism, and the band is noted on Metal Archives for having used at least five distinct logos across their history.

Infinity Horror was a death metal band from Assis, São Paulo, Brazil, formed in 2014 and later disbanded. Their debut recording, the demo Celestial Profanation, was released on February 17, 2014, and recorded at Estudio Improviso. The band operated within Brazil's underground old-school death metal circuit during their brief active period.

Infinity of Thoughts is a one-person atmospheric and depressive black metal project from Osasco, São Paulo, Brazil, founded in 2021 by the artist known as Valak. The project blends black metal with ambient and atmospheric elements, drawing influence from acts such as Summoning, Nargaroth, and Thy Light. Releases include the debut album When the Winter Ends (2021) and Aeterna Tormenta (November 2024), both available on Bandcamp.

Infortunia is a one-man raw black metal project based in Palhoça, Santa Catarina, Brazil, created in 2025 by the sole member known as Count Boulanger. The project has released two recordings, Aquilo Que Nós Vemos and Dissonance of Chaos, channeling a stripped-back, lo-fi approach to the genre.

Infortuno is a death/doom and hardcore band from Piracicaba, São Paulo, formed in 2022, featuring vocalist Bruno Lucas, guitarist Rodrigo Santos, bassist Bruno Reina, and drummer Bruno Lanza. The band released their debut EP, Decadent Vindication, in January 2023, a five-track record blending sludgy riffs and doomy breakdowns with NYHC-influenced drum grooves. They followed it in 2024 with Covenant of Dissent, a split release with Counterraid.

Infræterium is a death metal band from Bogotá, Colombia, active since 2016, previously operating as Dwellers of the Shadows. The band released a series of demos and singles throughout 2016 and 2017, including Sentinels, Portraits, and Veneno y Dolor, establishing themselves in the Colombian underground death metal scene.