Clamatorius is a black/death metal band from Goiânia, Goiás, Brazil, originally active from 1999 to 2005 under their own name after an earlier incarnation as Postumus (1998–1999). The band is notable for fusing extreme metal with Christian lyrical themes and released the five-track album "Consummatum Est" through Blackened Label Records.

Clan dos Mortos Cicatriz is a death-punk band from Curitiba, Paraná, Brazil, blending raw black metal, death metal, and hardcore punk into what the underground has called "nekro-hardcore." The band released their debut album "Técnicas de Morte" in March 2025 via Sentient Ruin Laboratories, a 15-track, 25-minute record described as a grim manifesto drawing imagery from slums, prisons, morgues, and war zones.

Claustro is a groove metal band from Buenos Aires and Hurlingham, Argentina, formed in 2011 by guitarist and vocalist Cristian Karpluk alongside guitarist Mariano Valsecchi, bassist Dante Roncali, and drummer Juan Marcelo Hernández Herrero. The band has released three studio albums — Pulsión Animal (2015), H.I.S. (2017), and En el umbral de la extinción (2020) — building a catalog that blends groove and thrash metal with hard rock influences.

Claustrofobia is a death/thrash metal trio from Leme, São Paulo, Brazil, formed in 1993, and widely regarded as one of the most important underground extreme metal bands to emerge from Brazil. The band has toured extensively through South America, Europe, and the United States — sharing stages with Slayer, Iron Maiden, Sepultura, and Napalm Death — and has released a string of albums including "Fulminant" (2005), "I See Red" (2009), and "Unleeched" (2022).

Clava is a death/thrash metal and hardcore band from São Paulo, Brazil, formed in 2024. The band operates in the tradition of Brazilian extreme metal crossover and is listed as active on Metal Archives. As a very recently formed act, they have yet to accumulate significant press coverage beyond their initial registration.

Clavicula Nox is a black metal band from Belo Horizonte, Minas Gerais, Brazil. The band's lyrical themes revolve around Satan, black magic, the occult, blasphemy, and nihilism, placing them squarely within the Brazilian occult black metal tradition. They are signed to Abrasax Distro & Records and maintain an active presence on both Facebook and Bandcamp.

Clawn is a brutal death metal band from Botucatu, São Paulo, Brazil. The band released two albums — "Deathless Beauty of the Silence" and "The Great Excuse to Domination," the latter recorded at SA Studio in Botucatu and widely praised as one of the finest Brazilian brutal death metal releases. The band received coverage from Whiplash.net, which called the album among the best of its genre produced in Brazil.

Clemency is a Christian death metal band from Londrina, Paraná, Brazil. The band released the demo "Satan's Funeral" (1998) and the full-length "Spiritual Domination" (1999), the latter reissued in 2019 via Warriors Records and Eirene Records. Their lyrical themes centered on Christianity, distinguishing them within Brazil's death metal underground.

Clenched Fist is a heavy metal band from the Jardim São Luís neighborhood in the south zone of São Paulo, Brazil. Drawing influence from classic 1970s and 1980s acts including Black Sabbath, Iron Maiden, and Dio, the band plays heavy/speed metal with lyrical themes touching on society and medieval imagery. They have released the albums "Homenagem aos Bravos" (2008) and "O Presente da Morte" (2012) and are signed to Infernö Records.