Nokturnal Mortum was originally formed as a death metal band called Suppuration in 1991, then turned to black metal and changed name to Darkness but "had to change the name back in 1993/94 to Nocturnal Mortum because there already existed a band with that name in Western underground". They have stated this about the current name and spelling: "We changed a letter so that we wouldn't find a band with the same name again like it was the case with Darkness". Nokturnal Mortum gained recognition in the underground Black Metal genre with the release of their debut albumGoat Horns, which had two keyboardists play on the album and for mixing traditional Ukrainian folk influences with BM. They focused heavily on atmospheric BM with themes common in classic nature-romanticism, often inspired by regional or local ancient folklore, mythology or journeys set in pagan landscapes. Early album art usually always depicted vast forests, swamps, sunsets, desolate mountains in wintery nights, and so on. The band's first albums were released through The End Records and by Nuclear Blast, but the label and the band separated at the time of the album releases of NeChrist and Lunar Poetry, both releases suddenly containing political support to neo-Nazi and White supremacist causes. The band began to change from being in the more popular extreme metal scenes to becoming one of the leading groups in the National Socialist black metal scene in Eastern Europe. Varggoth himself said about the conflict with the label: "We had a contract with The End Records but it was broken. We have different points of view. They didn't like our policy, we didn't like the way they do business. They owe us some money. That was enough for a conflict." Underground artist Igor Naumchuk had close ties with Nokturnal Mortum—who dedicated the album To the Gates of Blasphemous Fire to him—until all relations ceased due to ideological disagreements. Despite this, both bands are still likened to one another. In autumn of 2014, band frontman Knjaz Varggoth published a statement declaring that he and Nokturnal Mortum had begun to distance themselves from politics in order to avoid rumors concerning his personal views and band ideology; however, the band played live at the far right festival Asgardsrei in December 2016, and have played at several other right wing festivals since.
Initially, the band described their music as "lunar black metal". On the demo Lunar Poetry—later released as an album—the band advocated for the killing of Christians, the destruction of churches, and supported Slavic paganism, along with describing Jesus as a "crucified hippie". Later, when releasing their EP Marble Moon and also the Nechrist and Lunar Poetry albums, they included anti-Semitic lyrics with neo-Nazi and White supremacy messages and imagery. As the more popular non-political black metal scene began distancing themselves from their ideology, the band instead became prominent in the early Eastern European NSBM scene, and is today often considered as one of the groups that shaped the Slavic subcultural NSBM movement. They also began using swastikas in their logo, on albums, during shows, and praising the Third Reich and the Holocaust openly in various side-projects. Knjaz Varggoth, in one of several side projects, also voiced support for the so-called "racial holy war" idea. Nokturnal Mortum's NeChrist featured the song "The Call of Aryan Spirit", which included anti-semitic lyrics and glorified pogroms. The album included a swastika design consisting of four AK-47's. In interviews, appearances, merchandise and on their website, the band showcased neo-Nazi opinions but their music style itself was described as "pagan black metal". Statements and texts show neo-völkisch as well as neo-paganist ideas, and a tendency to ariosophy. In 2008, the band's vocalist and guitarist, Knjaz Varggoth, claimed that he had no interest in political tendencies and that he had, "never viewed Nokturnal Mortum as a political band"—despite the group at the time continued to support the right-wing Azov Battalion. In 2014 the group again stated that the band had severed ties with NSBM ideologies and political themes, but at the same time and in the following years, they remained active in white supremacist circles and has played live at neo-Nazi and far right shows, in collaboration with the NSBM label "Militant Zone". In July, 2018 the band continued to release anti-Semitic merchandise, such as re-releasing Nechrist in a box edition, which came with a temple-shaped candle with a crucifix, star of David, muslim crescent moon, and a hammer and sickle on it, for fans to burn.
