Atro is a blackened doom and death metal project from Campina Grande, Paraíba, active since 2019. The project operates in the underground extreme metal circuit of Brazil's northeast, blending the suffocating weight of doom metal with blackened atmosphere and death metal aggression.

Atrocitus is a thrash and metalcore band from Curitiba, Paraná, one of the more active names in the city's underground metal scene. Drawing on aggressive thrash structures alongside metalcore dynamics, the three-piece — featuring Huan Cruz on vocals and bass, Geert Giullian Strijker on guitar, and Pettrus on drums — has released singles such as "Veneno" and "Repulsa" and built a following through energetic live shows across the Paraná metal circuit.

Atrocity was a thrash metal band from São Paulo, active from 2004 until they split up, operating in the crowded but fertile São Paulo underground thrash scene. The band released material independently, continuing in the tradition of aggressive Brazilian thrash in the style of the São Paulo scene's old-school roots.

Atropelo is a crossover thrash band from Mauá, in Greater São Paulo, whose influences include Brazilian hardcore/thrash veterans Ratos de Porão, D.F.C., and Cólera. The four-piece released their debut album "Mentira Acima de Tudo, Ilusão Acima Todos" in February 2025, recorded at Hells Pass studio in São Caetano do Sul, with lyrics in Portuguese addressing political and social grievances.

Atropina is a death metal band from Teutônia, Rio Grande do Sul, founded in 1996 and one of the more enduring names in the gaúcho extreme metal underground. Starting with a thrash/hardcore edge on their 1998 demo "Louvar a Tudo por Nada" and the 2001 debut "Santos de Porcelana," the band evolved toward brutal death metal, later releasing conceptual albums including "Mallevs Maleficarvm" (2014) — which addressed the Inquisition — and "Prego em Carne Podre" (2021), with Portuguese-language lyrics consistently attacking organized religion and authoritarian structures.

Atrorium is a symphonic metal band from Teresina, Piauí, formed in 2018, representing an outlier in Brazil's northeast metal scene by pairing orchestral arrangements with heavy guitar work. The lineup features vocalist Camila Morais, keyboardist Cassio Carvalho, and guitarist Flavio Anderson, and the band operates independently in a region with relatively limited metal infrastructure.

Atroz is a heavy and progressive metal band from Juiz de Fora, Minas Gerais, with roots going back to 1998 under various configurations. Their self-titled 2021 release on Bandcamp marked a renewed presence, and the band draws on a range of heavy and progressive influences rooted in the fertile Minas Gerais metal tradition.

Atrymo is a death and black metal band from João Pessoa, Paraíba, formed in 2017 by members with roots in prior extreme metal projects. The four-piece — featuring Aracélio on drums and vocals, Ivan on bass and vocals, Ivaldo and Bruno on guitars — channels themes of human hatred, greed, and spiritual corruption through tracks like "Sentidos Infames," "Miséria e Ódio," and "Depressão," with lyrics sung in Portuguese.

Attack Fire is a thrash metal band from Cali, Valle del Cauca, Colombia, founded in 2010 and signed to Tanatofobia Productions. The band built a prolific catalog through the 2010s and into the 2020s, releasing splits and EPs including "Satanic Riffs" (2013) and "Habemus Tenebris Papam" (2014), and appearing on the 2013 Ultrametal Productions compilation "30 Years Of War, Fight, Sweat & Blood." Vocalist and bassist Kristhian Spinal has been a constant presence since the band's founding.