Macabro is a speed metal/punk band from São Paulo, Brazil, featuring Ruan Pablo on vocals, Gui Disanti on guitar, Naum Prado on bass, and Uriel Franco on drums. The band channels working-class protest energy alongside themes of Satanism and anarchy, and released the album "Mensageiros do Caos" (Messengers of Chaos) in December 2023.

Machocabrio is a stoner and hard rock band from Chillán, Chile who debuted with their album Altibajos in July 2015. The nine-track record blends stoner grooves, rock and roll energy, and Spanish-language songwriting in a style rooted in the heavy rock tradition.

Mad Dog is a heavy metal and hard rock band from Buenos Aires, Argentina, led by guitarist Martín Knye — a veteran of Argentine metal who previously fronted LZ2 (1986–1989) and recorded the country's first neoclassical metal album, El fuego sagrado (1989), before stints in Kamikaze, Magiar, and KZ4. The band features vocalist Javier "Oso" Muñiz, drummer Adrián Micheli, and bassist Diego Magnacca, and released a three-track EP in 2016 ("Dios Del Asfalto," "Huestes," "Mad Dog") followed by the ten-song debut full-length Hell Raising Breed in April 2020. Knye has cited Black Sabbath, AC/DC, and Black Label Society as primary influences, describing the band's sound as "pure, hard, and brutal rock."

Mad Roulette are a heavy metal band from Rio de Janeiro, Brazil, formed in 2014, composed of Marcio Abud on guitar and vocals, Andre "Cheddar" on bass and vocals, and Marcos Soli on drums. The band released the full-length Turn the Wheel in February 2018 through MS Metal Records, delivering nine tracks of straightforward heavy metal with prominent riffs and forceful drumming.

Malacara is a veteran Buenos Aires heavy metal band with two albums listed on the Metal Archives: "Vuelvo a tu camino" and "Mi rebelión". The band appeared on the 2006 Argentine tribute compilation "El Barón Vuela Sobre Argentina — Tributo a Barón Rojo", contributing a cover alongside bands such as Riff and Lethal.

A traditional heavy metal outfit from Sorocaba, São Paulo, Maligna operated within the classic mold of melodic riffing and anthemic song structures before disbanding. Their work reflected the enduring influence of 1980s heavy metal on the Brazilian underground circuit.

A short-lived São Paulo act, Maligun worked the intersection of metalcore and traditional heavy metal during their active years between 2013 and 2019, drawing on the city's rich lineage of heavy music while incorporating the rhythmic aggression of the metalcore idiom. The band remained independent throughout their existence before eventually splitting up.

Manifiesto is a thrash and heavy metal band from Morón, Buenos Aires, led by guitarist Cristian González, with a catalogue that spans from their first album Insano (2006) through La Obra Maestra del Odio (2015) to La Ley del Talyon (2024). After nearly a decade between studio records, the band's 2015 comeback album was reviewed across Argentine metal media including Metal-Daze Webzine and Metal Argento, cementing their standing in the local scene.

Mantra Heavy Metal is a heavy metal band from Buenos Aires, formed in 2001 by vocalist Eduardo Paredes, guitarist Walter Sobrero, bassist Ramiro Cora, keyboardist Luis Cosenzo, and drummer Ariel Behrend. The band self-released a seven-track demo in 2003 and returned a decade later with the full-length Perder Para Ganar in 2012.