Kizilia is a metalcore band from Belém, Pará, Brazil, formed in 2016 by a group of friends who had previously played together. In a prolific early run, the band released four records — Cidade Sitiada (2017), Em Suas Mãos (2018), Realidade Ficção (2019), and Sagrado Sacrifício (2019) — with lyrics addressing social violence and the realities of life in their region. The lineup features Roy on vocals, Manassés on drums, Fabricio on bass and backing vocals, and Black on guitar.

Kizin is a progressive death metal project from Temuco, Chile, founded by multi-instrumentalist Luis Peña Otto, who draws on the philosophies of Nietzsche and Schopenhauer to craft conceptual albums with long-form tracks and technically demanding riffs. Their debut Abstraction (2018) was described by No Clean Singing as a "progressive death metal fireworks display," and their follow-up Existentialism (2021) — recorded across Temuco and Leipzig — continued the project's thematic arc through six tracks organized into three narrative chapters.

Kliffoth is a black metal band from General Roca, Río Negro, Argentina, active since 2001 and drawing on themes of fantasy, occultism, and Viking mythology. The band released demos in 2003 and 2006, and their full-length album "Infinitum Tenebrarum" appeared in 2014. They also contributed the track "The Golden Walls of Heaven" to "Odens Ride Over Southernland — An Argentinean Tribute to Bathory" (2013).

Knife of Melqart is an anonymous black metal project from Buenos Aires whose membership is deliberately concealed. The band debuted in October 2013 with the EP "Lord of Tyre" and followed it with "META ƟHPION" in May 2016, drawing coverage from outlets such as No Clean Singing. Their later single "Sovereign Prince of Rose Croix" continued their exploration of occult and Phoenician-tinged themes.

Kocytus is a progressive death metal band from São Paulo, Brazil, whose name is drawn from Dante's Divine Comedy — specifically the frozen ninth circle of Hell. The band released their self-titled debut full-length on October 31, 2024, a 59-minute independent record featuring nine tracks that blend technical death metal with progressive structures. The album's thematic scope spans cosmic horror, heresy, and Dantean imagery.

Koriza is a thrash/death metal band from Ilhéus, Bahia, Brazil, with a listing on the Encyclopaedia Metallum that includes the demo "Defluxo" among their early releases. The band operates out of a city better known as a literary landmark — the birthplace of writer Jorge Amado — making them a notable presence in Bahia's underground extreme metal scene. They have maintained an active Spotify presence alongside their long-running career.

Korvak is a thrash metal band from Campina Grande, Paraíba, Brazil, formed in 2019 and signed to NoSlip Records. Influenced by old-school death and thrash of the 1980s and early 1990s, the band draws lyrical themes from occultism and social criticism. Their 2023 full-length Chapter II — World's Duality stands as their most developed release, recorded across multiple studios and featuring twelve tracks of aggressive, riff-driven thrash.

Kosmus is a progressive metal band from Rio de Janeiro, Brazil, founded by guitarists Pedro Acker and Sebastian Viret. The band released a self-titled debut album in July 2016, followed by Eudaimonia in 2018, blending heavy riffing with progressive rock textures, jazz-influenced keyboards, and saxophone. Their lineup expanded to include bass, keys, and drums to realise an ambitious fusion of metal and Brazilian progressive music.

Kraftvøid is a São Paulo-based instrumental stoner/doom metal project founded by Gustavo Lima in March 2020. The project pursues a raw, organic approach to heavy music and released its self-titled debut album in January 2022, featuring tracks such as "I Am The Emptiness" and "Fire of a Thousand Suns." Operating without a Spotify presence, the project distributes its music independently through Bandcamp.