Monster Mash channel the early German speed/thrash scene — citing Vectom, early Blind Guardian, and Iron Angel as touchstones — with high-energy performances anchored by the versatile vocalist Lion. The band surfaced with the demo He Gambled with Satan and Lost, a three-song statement that mixes traditional and extreme thrash with tight cohesion.

Morbid Devourment are a death/thrash trio from Brasília who consciously root their sound in the primitive filth of early-80s metal, citing Venom, Hellhammer, and Bulldozer as touchstones. Their 2025 debut EP Deathstrike Rebellion packs nine songs into eighteen minutes of raw, occult-themed extremity, following earlier singles that established the band's violent aesthetic.

Morbid Holocaust is a black metal band from Valparaíso, Chile, operating primarily as a one-man project under the name Holocausto. The band released their debut album Atmospheric Armageddon in 2017, recorded at Calaka Records in Valparaíso, and the full-length Conexiones in 2023, the latter tracked between 2021 and 2023 at IIgniter Studios in Limache; they also contributed to the five-band split En el Caos de la Oscuridad alongside Morgue, Kalkü, Beelzebuth, and Ausencia in 2023.

Morbo Chacaleitor is a death/thrash metal band from San Felipe, Chile. The band released two albums in quick succession: Crónicas Macabras in October 2019 and Inconsciente Asesino in September 2020, the latter a six-track record featuring Spanish-language tracks rooted in violent and urban themes.

Mordrom is a continuation of Crux Cullum, a band that ran from 2007 to 2016 before being resurrected under this name in 2024. The project blends death metal with thrash and black metal undercurrents, channeling themes of occultism, misanthropy, and anti-religion, with the album "Walking to Bloody Death" representing their current direction.

Moretools emerged from the Brasília underground with a self-titled debut that fuses death metal, grindcore, thrash, and hardcore into a relentlessly aggressive whole. The band has shared stages with Krisiun, Onslaught, and Torture Squad, and appeared at major festivals including Porão do Rock.

Originally founded as Morticínio in 1998, Mortage play a brand of speed and thrash metal that follows the aggressive European template — early Kreator is a clear touchstone — with fast riffing built for relentless headbanging. The band has appeared on international splits, including a vinyl release alongside Californian thrash veterans Hirax.

MortalDread emerged from the same orbit as the earlier Goiás underground project Selbstmord, carrying on a tradition of aggressive, uncompromising thrash metal from the center-west of the country. The band released material independently before splitting up, leaving behind a document of the city's underground metal activity.

Operating out of Rondônia's small but tight-knit metal community, Morte Lenta plays raw, no-frills thrash with roots in Destruction, Slayer, and early Sepultura. The band released a demo in 2016 and has continued building a catalog rooted in the stripped-down, aggressive side of the genre.