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).

Insorcist is a death/black metal band from Santiago, Chile, originally formed in 2002 under the name Azael before adopting the current name and recording the three-track demo Donfallen Kingdom in 2003. The band released the EP Eternal Torment in 2006 and their debut full-length The Slaughter of Divine Creed in 2011 through Apocalyptic Productions, a nine-track concept album recorded at Sade Studios with lyrics exploring anti-Christian and occult themes.

Interitvm was a black metal project from Viña del Mar, Chile, operating as a personal venture of Omega, lead guitarist of Chilean black metal band Indoctrinate. The band released the Extermination promo in 2014, followed by the self-released EP Reign of Nuclear Apocalypse in 2017 — a seven-track assault of war-themed black metal that was later reissued on CD in 2023 with bonus tracks through Seven Headed Beast and Deathcamp Records.

Into Morphin is a death/black metal band from Teresina, Piauí, Brazil, active since 2021. The band's confirmed lineup includes Mvreisc on vocals, Yansilva and Padua Belo on guitars, Maxribeiro on bass, and Helio on drums, making them one of the few extreme metal acts operating out of Brazil's northeastern state of Piauí.