Katharzian is a symphonic and melodic black metal band from Manaus, Amazonas, Brazil, founded by vocalist Roosivelt Gomes and keyboardist Cecília Katrini, with a full lineup that includes guitarist Rômulo Toyoda, bassist Matheus Santos, and drummer Thiago Leão. The band released their debut album Purgatory in 2017 through Eternal Hatred Records, blending atmospheric black metal with symphonic and progressive elements. They performed a notable live set at the Anhangá Green Festival III in Manaus in August 2022, documented as a live release on Metal Archives.

Katástrofe is widely regarded as the longest-running thrash metal band in Campo Grande, Mato Grosso do Sul, with roots tracing back to 1994. Over their career the band has shared stages with major Brazilian metal acts including Dorsal Atlântica, Vulcano, and Ratos de Porão, and built their following on tracks such as "Labirinto da Morte" and "Pax Romana." The current lineup features Fernando Alemão on drums, Roberto on vocals, Faiska on bass, Eduardo Kadaver, and Lelo Reinoso on guitars.

Kausa y Efecto is a thrash/crossover band from Viña del Mar, Chile, playing in the tradition of the Valparaíso-region extreme metal scene. They released the album Estado de Control and have performed alongside acts such as Torturer, Acrostic, and Metastasis at Chilean metal festivals including Bay Area Assault.

Kaustik is a stoner metal band from Jundiaí, São Paulo, Brazil, with a history tracing back to 2000. The band released their album Hard Drugs in 2009 as an independent release, drawing on heavy riff-driven stoner rock and metal aesthetics. Their lineup has included Mark Nomad on vocals and guitar, Dirty Robbi on bass, and Richard Badguy on drums.

Kavla is a heavy metal and hard rock band from São Paulo, Brazil, with origins dating to 1992. The band released the album Dream or Reality in 1995 and returned after a hiatus with Surreal in 2008, building a catalog rooted in melodic traditional heavy metal. Their current lineup features Thiago Cicilini on vocals, Sandro Silva and Fábio Silva on guitars, Carlos Ceroni on keyboards, Marcelo Eiger on bass, and Nina Pará on drums.

Keep the Rage is a melodic groove metal band from Bogotá, Colombia, formed in 2019. The group has released a series of singles including "Awake," "Invader Souls," and "Hidden in the Shadows," with members also active in bands such as Blazing and Ripping Flesh.

Keophsia is a melodic heavy metal band from Campinas, São Paulo, Brazil, formed in 2016. The band released their debut album Loneliness in January 2016, a ten-track record blending melodic and traditional heavy metal elements. They have maintained an independent presence on Bandcamp and SoundCloud since their formation.

Kerix was a symphonic/gothic metal band from São Paulo, Brazil, signed to Megahard Records. The band contributed the track "New Land" to both Metal Storm VI (2013) and Metal Storm – Christian Metal from São Paulo (2015), establishing them within the Brazilian Christian metal underground. They have since split up.

Kernunna is a Celtic folk metal band from Varginha, Minas Gerais, Brazil, formed by members of Tuatha de Danann and guitarist Khadhu Capanema of Cartoon. The band blends progressive rock textures with folk metal, featuring instruments including uilleann pipes, tin whistle, violin, and bouzouki. Their debut album The Seim Anew (2013) spans nine tracks and showcases the project's fusion of Celtic and Brazilian musical sensibilities.