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.

Clint X Eastwood is a raw black metal and grindcore band from Catanduva, São Paulo, Brazil, formed in 2023. The band's lyrical themes revolve around Clint Eastwood films, an unusual conceptual hook within the Brazilian underground extreme metal scene. They released a self-titled demo in May 2023, available on Bandcamp.

Cloud of Shadows is a metalcore band from Quilmes, Buenos Aires, Argentina, whose sound is rooted in the Gothenburg melodic death metal tradition with clear influences from In Flames, Arch Enemy, and Dark Tranquillity. The band released their third album Rodeando el Abismo in 2022 and have maintained nearly continuous activity, with a fourth studio record in progress as of 2026.

Coagular is the solo progressive death metal project of Christian Barzallo, an Ecuadorian musician from Quito previously known as the vocalist of Reject Messiah and a member of Ergosvm and Vril. The project blends death metal, grindcore, and progressive metal into a melodic and introspective sound, with releases including the 2025 EP Edictvm Perpetvvm.

Coagulo was a death metal band from San Juan, Argentina, formed in 2015 and later split up. The five-piece lineup featured Julián Ibars on vocals, Martín Manrique and Julio Rosales on guitars, Elías Vega on bass, and Daniel Fernández on drums.

Cobalto was a thrash metal band from Salvador, Bahia, Brazil. The band's lyrical themes encompassed politics, evil, and darkness, and they released the album "Elemental" on Torto Fono Gramas before eventually splitting up. They are listed on Metal Archives as a defunct act.