Ahiag is a death/groove metal band from São Paulo formed in 2018, blending the rhythmic heaviness of groove metal with death metal aggression. Their 2019 single "Malfeitor" offered an early look at their dense, riff-driven attack within São Paulo's active underground metal scene.

Ahriman was a death metal band from Recife, Pernambuco, active from 1997 until their split-up and named after the Zoroastrian deity of darkness. Operating out of the northeast Brazilian underground, they were part of Recife's burgeoning extreme metal scene of the late 1990s.

Ahura Mazda is a traditional heavy metal band from Pouso Alegre, Minas Gerais, with roots stretching back to 1992 before reforming in their current incarnation around 2012. The band features a twin-guitar lineup and recorded a demo in 1994, drawing on classic heavy metal influences while operating as an independent act in the Minas Gerais underground.

Ahínco is a progressive death and thrash metal band from Mar del Plata, Argentina, active since 2013 with a lineup anchored by Lucho Alippi on bass, vocals, keyboards, and synths, Hernan Chave on guitar, and Ariel Sanchez on drums. Their prolific Bandcamp catalog includes releases such as La Canción de los Sepulcros (2020) and Quem Deus vult perdere, prius dementat (2021), the latter recorded at UC Dadson studio in Mar del Plata and mixing atmospheric depth with technical intensity. The band's work spans Spanish-language lyrical themes with a compositional range that draws on both death metal aggression and progressive architecture.

AISA are a heavy metal and hard rock band from Santiago formed in 2019 by Julio Soto (bassist of SteelRage and DarkSpell) alongside vocalist Eva Murgas (of Beerhalla). The band debuted with the single "Let Us Rock" in November 2019 and released their full-length album "Join Me to Metal" in 2022, a 10-track record issued on CD in a limited edition of 300 copies.

Aizen is a classic heavy metal band from Rosario, Argentina, drawing on the sounds of Judas Priest, Scorpions, and early hard rock. The band released their debut demo in 2020, recorded at Studio Paramo in Rosario, and contributed the track "Warrior Through Time" to the Argentine compilation Nueva ola del heavy metal Argentino in 2021. The current lineup features Gabi Franc on lead guitar and vocals, Guillermo Luna on bass, and Lautaro Trevisan on drums.

Ajayu is a black metal band from El Alto, Bolivia, signed to Infernal Possession Productions. Their self-titled full-length, released in 2017, is described as a work drawn from the soul exploring the complex nature of human emotion, placing them within a small but active circle of extreme metal acts operating out of Bolivia's high-altitude urban centers.

Ajeno is an instrumental sludge and groove metal band from Buenos Aires, Argentina, known for heavy, riff-driven compositions without vocals. The band released their self-titled EP followed by Justificando el Kaos in November 2024, a three-track record recorded at Estudios Inclan and La Ochava Records. Both releases showcase a dense, slow-burning approach rooted in the heavier end of sludge and post-metal.

Ajna is an industrial thrash metal band from São Paulo fronted by vocalist Elizabeth Queiroz (known as Tibet), blending guttural female vocals with samplers, industrial collages, and aggressive thrash riffs. Originally formed in 1990 and reunited in 2015, they released the EP "War Crimes" in 2019 — produced by Marcelo Pompeu of Korzus — and have performed at venues including Centro Cultural São Paulo and festivals such as Metal Attack.