B on Reason is a heavy/thrash metal band from Pernambuco, Brazil, formed in 2021. The project spans multiple releases including albums titled The Mission, Endless Siege, and The Empire of Lost Souls, carving out a self-described universe of metal, game, and multimedia content. Their sound sits in the classic heavy metal and thrash tradition rooted in the Northeast Brazilian underground.

Baalberith was a raw black metal band from São Luís, Maranhão, Brazil, active from around 2002 and eventually split up. The band recorded two demos — Porco Destronado (2005) and Escalada Triunfante (2007) — before releasing Black Metal Militia on CD-R through Depressive Illusions Records in 2013. Their lyrical themes centered on blasphemy, hate, and profanity in the uncompromising tradition of South American black metal.

Baba de Sheeva is a thrash/crossover band from Goiânia, Goiás, Brazil, bringing the fast and irreverent spirit of the genre to the Central-West metal scene. Formed with themes revolving around life, religion, drinking, and weed, the band released the CD-R É Triste O Destino Da Maioria Dos Homens in 2011 and has remained an active presence in the Goiânia underground. Their sound blends the aggression of old-school thrash with the punk energy of crossover.

Backbone is a progressive death metal band from Resistencia, Chaco, Argentina, emerging from the ashes of previous local projects including Melisma and Alhazred. Their debut EP "R'lyeh"—titled after the sunken city of H.P. Lovecraft's mythology—drew notice for combining death metal brutality with groove and progressive elements unusual for the region's underground scene.

Backstroke is a thrash metal band from Brasília, Brazil, formed in 2019. Operating out of the capital's underground scene, the band channels straightforward, aggressive thrash in the Bay Area and Brazilian tradition. They remain active as an independent act in the Brasília metal community.

Bacteremia is a Brutal Death Metal band from Medellín, Colombia, formed in 2006 and signed to Permeated Records. They released their debut full-length "Cerebral Wrong Settings" in 2013, followed by "Furiously Reduced" in 2017, a nine-track album exploring themes of mankind, death, and pathology.

Bacteria is a heavy/thrash metal band from San José, Entre Ríos, Argentina, active since 1999. The band appeared on the 2009 compilation "2dos. Puro Metal" released by Kodigo Rojo Records out of Concordia, Entre Ríos, one of the few regional metal labels documenting the underground scene in that province.

Bad Resilience is a grindcore and noisecore project from São Paulo, Brazil, founded in mid-2024 by musician Rodrigo Chenta. The project fuses diminutive riffs with raw blast-beat grind, drawing lyrical themes from Christian theology — including kenosis, ordinances, and martyrdom — with lyrics in both English and Spanish. Their debut album Mutilated Head (2024) arrived alongside the single Stoning, establishing a deliberately brutal and theologically charged identity.

Bad Salad is a progressive metal band from Brasília, Brazil, formed in 2007 by brothers Thiago Campos (guitar) and Felipe Campos (bass) alongside drummer Caco Gonçalves. Their debut album Uncivilized (2012) earned international critical acclaim for its complex songwriting and songs regularly exceeding ten minutes, drawing comparisons to Dream Theater and Opeth; the follow-up EP Puzzled appeared in 2013. The band was handpicked by Mike Portnoy to perform on the Progressive Nation at Sea cruise in 2014, one of the few Brazilian acts to achieve that distinction.