Os Capial channel the interior São Paulo caipira culture into abrasive grindcore, with lyrics, imagery, and speech all rooted in the rural working-class world their name pays tribute to. Since their 2015 debut Nossa Grindroça Querida they have maintained a prolific pace, releasing titles like Grindiagem Deatherra (2016), Emboscada Caipira de Plasma (2017), and Chichá - Sterculea Foetida (2018), each one hammering the collision of regional identity and extreme noise.

Formed by Daemon Lutor and Licantropo, Osculum Infame traffic in bestial black/death metal rooted in the Amazonian underground, releasing their debut Eras Abissais in 2017 and following it with Nuclear Alfa Caos in 2022. Their sound sits in the war metal tradition — raw, blasphemous, and relentless — and they have also appeared on splits including the Holocausto da Luxúria Bestial split with Bode Profanador.

Osculum Obscenum built their reputation on ferocious black metal shot through with grindcore aggression, with their 2003 album Body Hurting Art cited by Brazilian underground historians as one of the most significant extreme metal releases the country produced in that era, alongside landmarks like INRI and Wicca. They later returned with material including Engendrum and Avances de Muerte before eventually disbanding, leaving behind a catalog regarded as visceral and uncompromising even by the standards of the Satanic underground.

Oscuro Mito is a black/folk metal band from Cochabamba, Bolivia, formed in 2008 and released through Catáfila Producciones. Their music draws heavily on Andean themes — Inca and Aymara culture, ancestral legends, and indigenous paganism — which sets them apart within Bolivia's extreme metal scene. The band released their debut full-length Yuraq Ushpa in 2019, following years of demos and split appearances including the 2015 compilation Holocausto Zine.

Ospetor is a raw and atmospheric black metal project from Loja, Ecuador, formed in 2020 and operating under strict anonymity — no names, no identity, no ego. Their 2020 debut Demo I, recorded at Umbral Xtudio/Dungeon Rec, delivers visceral and primitive black metal rooted in the virulent South American underground tradition. Released through Sutsircitna Productions, the band draws comparisons to acts like Satanic Warmaster for their uncompromising, trance-inducing approach to the genre.

One of the most enduring crossover/thrash acts from the Serra Gaúcha region, Ossos fuse the aggressive tempo of hardcore with heavy thrash riffs in a style forged through decades of relentless live activity. Their 2018 album Caos em Mim was followed by Contos do Necrotério, cementing a reputation as one of southern Brazil's most committed names in the crossover underground.

Formed in Belo Horizonte in 2012 by members steeped in Venom, Bathory, and Hellhammer, Ossuário play raw, uncompromising black/speed metal soaked in occult darkness and stripped-back aggression. Their debut EP Metal Antichrist (2016) established their reputation in the national underground, and the 2025 follow-up Metal Póstumo — released on cassette by Morbid Ways to Die and on CD by Cianeto Discos — continues that tradition with the current trio of Coveiro, Necrolsky, and Splatter.

Osteoporosis Aguda is a death metal band from Cantaura, Anzoategui, Venezuela, formed in June 2014 by Ruth Figueredo and Luis Enrique Gomez. The band has released a debut full-length, "Suenos de eterna oscuridad..." (2016), and continued with split appearances and the EP "Bienvenida oscuridad, PT.1: Palingenesia" (2023).

Othuyeg is a death metal band from Córdoba, Argentina, formed in 2017 by guitarists John Long and Syd Xöxō, vocalist Leonardo, bassist Facha, and drummer George Corpsefucker. After a self-titled demo and the "II" EP (2018), the band released their debut full-length "The Doom Walker" in February 2020, a blackened and dissonant death metal record noted for its gritty production and unconventional vocals. They continued with the "Inanis Imago" EP in November 2024, extending their exploration of technical, dissonant extreme metal.