Incredulus is a blasphemous black metal band from Contagem, Minas Gerais, Brazil. The band released the album Aos Ímpios in 2009 as a CDr, a ten-track work with Portuguese-language titles issued independently and later distributed through Australis Records.

Infected Morchirium is a black metal band from Maringá, Paraná, Brazil, formed in 2023, featuring Ghvme on vocals, Chicxvlvb on guitar, and Danilo Campaner on drums. The band released their debut album "Luciferum" on December 1, 2023, a nine-track record produced and mixed by Danilo Campaner with cover art by Roberta Maria Fernandes. Lyrically the album engages themes of antifascism, anti-colonialism, and opposition to religious hypocrisy, placing the band within the Red and Anarchist Black Metal tradition.

Inferi is a black metal band founded in Buenos Aires, Argentina by drummer Inferi Black (Sebastián Rodríguez), who released the debut album "The Call of the Dark Side" in 2000 and went on to record "The End of a Weak Nature" (2009) before relocating to Austria in 2013. After a hiatus, the band reformed in 2018 with a new lineup and released the fourth full-length "Fourth Portal" in April 2020.

Infernus is a black metal band from Rosario, Santa Fe, Argentina, whose lyrical themes center on Satan, wolves, and war. The band released the album "Xul Eterna" in 2012, a work documented on Metal Archives and reviewed in the Argentine underground metal press. They remain an independent, unsigned act within the Rosario extreme metal scene.

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.

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 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.

Inner Abyss is a black metal and dungeon synth project from Ushuaia, Tierra del Fuego, Argentina — one of the southernmost cities on Earth — formed in 2011. The band released their self-titled debut album in September 2011, followed by the EPs "Outer Space" (2014) and "Totengesänge" (2015), and the album "Don't Dream It's Over" in 2023. Their catalog blends raw black metal with atmospheric synthesizer work, and the project maintains an active Bandcamp presence.

Insomnio is a solo project founded in 2016 in Concepción, Chile by Francisco Acuña Inzunza, also known as the bassist of thrash/speed metal band Crushing Brain. The project blends neofolk, doom, and black metal with themes of melancholy, desolation, nature, and mortality, and has released a prolific run of albums since 2020 including Anónimo (2020), Canto a la desolación (2021), Umbrío (2022), and Danza silenciosa de su muerte (2023).