Martyrdom have spent decades honing a suffocating brand of death/doom rooted in occult and ancient civilizations imagery, with slow, mournful riffs giving way to cavernous death metal blasts. After a 1997 demo and years of obscurity, they released the EP "Culto Primitivo à Morte" in 2017 and their debut full-length "Ritual Místico de Adoração à Sabedoria Ancestral" in 2018, recorded at Netuno Estúdio and mixed in Montreal.

Martyrium wove Gothic and Doom Metal together with lyrics drawing on literature, fantasy, and Thelemic philosophy, bringing a distinctly introspective and melancholic tone to the Minas Gerais underground. The band, whose Bandcamp release "Abandon Hope" captures their brooding sound, was short-lived, splitting up not long after forming in the early 2000s.

Martyrizer played short, abrasive grindcore in the tradition of the Belo Horizonte extreme underground, releasing the six-track "Sick Music To An Extreme World" in April 2014. They also appeared on the compilation "Crushed Vol. II" and performed live that same year at the Metal Punk Overkill III festival before eventually disbanding.

Masacritika is a stoner metal and heavy rock band from Santiago, Chile, formed in May 2015. Drawing on influences including Black Sabbath, Sepultura, and Corrosion of Conformity, they released their debut EP Homónimo in 2017 and their first full-length Thesis Mortem in January 2020, followed by the EP Raza de Kain in 2022, released simultaneously in Chile, France, and Costa Rica.

Formed in 2020 by vocalist Yves Schneider, guitarist Israel Bianchi, bassist Dangelis Britto, and drummer Vinicius Brasil, Masennus fuse death metal's density with grindcore's aggression and tackle themes of existentialism, inner struggle, and social decay. Their debut demo "Phobos Terrorizer" and the follow-up "Disturbing Pandemic Incantations" — which includes a caustic cover of Björk's "Human Behaviour" — both appeared within months of the band's formation.

Mask of Semblant is a deliberately anonymous progressive/melodic death metal outfit whose members have kept their identities hidden since the band's formation. Their debut EP Existence (2017) mapped the Four Horsemen of the Apocalypse across six tracks, while the follow-up Dead Tales (2018) shifted the lyrical lens toward earthly decadence and civilizational rot, both recorded at Socoloski Recordings in Florianópolis.

Masochrist was a black metal band from the Florianópolis/São José area that emerged in 2011 and released a run of compact, raw recordings before splitting up. Their debut EP Enter The Masochrist (2011) was followed quickly by Karmageddon (2012), both leaning into a corrosive, lo-fi black metal attack rooted in Satanic and misanthropic themes.

Mass Mayhem blends metalcore aggression with power metal melodicism and epic tonal ambitions, tracing their roots to the duo project Primacy launched by cousins Lucas Sodré and Marcos Paulo in Parauapebas. The band signed with MS Metal Records and released material under the Mass Mayhem name, building a following in the far northern Pará state scene.

Mass of Souls combine black metal bleakness with gothic doom atmosphere, drawing clear influence from Candlemass — their self-titled demo even included a cover of the Swedish legends' "Solitude." The project surfaced in 2019 with the single Tales of a Rebel Soul, establishing a sound that sits at the darker, more sepulchral end of the doom spectrum.