Orgullo Fisura is a heavy punk band from Buenos Aires, Argentina, who fuse traditional heavy metal with punk aggression and socially charged lyrics rooted in underground resistance culture. They released "El infierno del heavy punk" in 2015 on Desatan Records, followed by "Derribando muros" on the same label in October 2018. The band has been a consistent presence in the Buenos Aires underground scene, with a catalog that also includes earlier releases such as "HeavyPunk de carretera" (2017).

Orion were founded at the end of 2001 in San Javier, a town in Chile's Maule region, with the stated aim of channeling the spirit of 1980s thrash and death metal. The band released their debut full-length Mysterivm Cosmographicvm in September 2020 through Iron Blood and Death Corporation, recorded and mastered at Equinox Studios in Rancagua, weaving philosophical and ancient-world themes through nine tracks of old-school death/thrash.

Orizzon bring a four-piece lineup — vocalist Tiago Pierucci, guitarist Marcos Duran, bassist Leonardo Gonçalves, and drummer Fabricio Mendonça — to a sound that fuses classic heavy metal muscle with progressive songwriting ambition. Their 2024 debut "Inner" confirmed the band's intent to bridge old-school power and modern technical sensibility without defaulting to either extreme. The result is a progressive metal record that values memorable hooks alongside compositional depth.

A solo project by multi-instrumentalist Danilo Rakkaus, Ormsdóttir debuted in early 2024 with the three-song EP Children of Sin, drawing from classic Black Sabbath-style doom while threading in stoner and depressive textures. The tracks range from driving, energetic riffs to slow, heavy passages, making a compelling first statement for a one-person outfit with a clear ear for contrasting moods.

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.

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.