Orthostat play a dense, riff-heavy style of death metal with an ear for odd time signatures and shifting dynamics, from doom-laden crawls to blastbeat surges. The band's 2019 debut full-length Monolith of Time, recorded at Hell Frost Studio by vocalist-guitarist David Lago, weaves its themes of ancient civilizations and cosmic scale into an album that reviewers praised for being unusually memorable within the old-school death metal field.

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.

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.

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.

OUDN — short for Our Ultimate Dying Nightmare — blend melodic modern death metal with groove-driven riffing and a polished production sensibility. Their catalog includes the EP Save Us from Ourselves (2016) and the full-length Time to Decay (2018), which display a sound that favors rhythmic punch and melodic hooks over pure extremity.

Named after the legendary ghost ship whose crew perished under mysterious circumstances, Ourang Medan channel that maritime dread into slow, crushing sludge and doom built around themes of cosmic horror and the occult. Their debut full-length Lords of Eternal Seas (2016), recorded at Estúdio Warsong in Natal, captures a dense, ritualistic heaviness that earned them recognition as one of the northeast's standout underground acts.