Kat (Polish for “executioner”) was formed in late 1979 by drummer Ireneusz Loth and guitarist Piotr Luczyk – bassist Tomasz Jaguś and guitarist Ryszard Pisarski later joined the band. They played instrumental music until mid-1982 when Roman Kostrzewski took vocal duties. Their sound was clearly reminiscent of '70s hard rock and the NWOBHM, later embracing a thrash-oriented sound.

In 1984, Wojciech Mrowiec replaced Pisarski and the group qualified for the band contest of the Jarocin festival. Their increasing success gave them the opportunity to record their debut single Ostatni Tabor/Noce Szatana the same year with the collaboration of Tomasz Dziubiński. In May 1985 they toured with Hanoi Rocks and headlined the Jarocin festival.

They signed shortly afterwards with the Belgian record label Mausoleum Records, which released the English debut Metal And Hell, which was published in March 1986. The Polish version 666 was released by Klub Płytowy Razem in 1987. The album became a cult item among fans. The band sparked controversy with their satanic lyrics and celebrations of black masses in cemeteries.

Bassist Krzysztof Stasiak was subsequently introduced, while Mrowiec presented his resignation in 1987. The same year, Kat toured with Metallica in their home country and gigged alongside Overkill, Helloween and Running Wild at the Metalmania festival, releasing the live album 38 minutes Of Life in December.

In late 1987 they also recorded Oddech Wymarłych Światów, finally published one year later. The band parted ways with Dziubiński at the time, marking the beginning of a period of crisis. They disbanded in 1988, following Kostrzewski’s departure.

It wasn’t until 1990 when Kat was reactivated, adding new bassist Krzysztof Oset and guitarist Jacek Regulski, going on tour with TSA and Acid Drinkers, later appearing at the Jarocin festival. This new formation recorded Bastard in 1992 and Ballady in 1993. In 1995, Kostrzewski’s debut solo album Biblia Satanistyczna was released and labeled as Roman Kostrzewski & Kat, but it’s not considered part of the band’s discography.

Following records ...Róże Miłości Najchętniej Przyjmują Się Na Grobach released in 1996 and Szydercze Zwierciadło in 1997 showed a marked change in the group’s sound. Kat suspended activities after the tragic death of Regulski in a motorcycle accident in 1999.

The band was reactivated in late-2002, touring and playing in most big cities in Poland. In 2004, Kostrzewski and Loth quit and formed Kat & Roman Kostrzewski due to musical differences, playing songs of the band live, which led to legal battles with Luczyk.

Drummer Rogol, second-guitarist Jarek Gronowski and singer Henry Beck completed the new line-up which recorded Mind Cannibals entirely in English, which saw the light of day in October 2005 through Mystic Production. European dates with Six Feet Under and a couple of concerts in their home country sharing stage with Helloween followed. In 2007, they signed a distribution deal with Karthago Records, and a license deal with Nuclear War Now! Productions, which released their albums Mind Cannibals, 666 and Metal and Hell on limited edition vinyls.