Kimera is a thrash metal band from Castelar, Buenos Aires, Argentina, formed in 2008, featuring vocalist Francisco Diaz, guitarists Maty Diaz and Danny Almeida, bassist Fernando Díaz, and drummer Gonzalo Rillo. The band released their debut full-length En Tiempos Violentos in 2017, followed by the two-track EP Esclavos Hoy y Ayer in August 2019.

Kinoglass is an experimental thrash/groove metal trio from Presidente Prudente, São Paulo, Brazil, formed in 2020, comprising Luis Farrús (bass/vocals), Fernando Volpin (guitars/keyboards), and Guilherme Sala (drums). They released the nine-track album A Man With A Camera in March 2020, followed by Se A Carapuça Servir in February 2024, with both records blending thrash aggression with psychedelic and avant-garde influences rooted in 1970s heavy rock. Their lyrical themes address social criticism, anti-fascism, and personal struggle.

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.

Knightrider is a thrash/death metal band from Salvador, Bahia, Brazil, documented on the Encyclopaedia Metallum with a discography that includes the war-themed demo "War" (2003). The band's lyrical content centers on the subject of war. They remain an independent act within the underground metal scene of northeastern Brazil.

Knock Out is a heavy metal and hard rock band from Buenos Aires, Argentina, formed in 2013. They released the eleven-track album "Sin Vergüenza" in May 2015, and later appeared on the CROM Records compilation "CR 021 — Nuestro Infierno" (2021) with the track "Pisando Fuerte". The band operates as an independent act and maintains an active presence on Bandcamp.

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.