All started in March 1996, with the group "Undertakers", developing a Thrash style of the 80s: Kreator, Slayer, Sodom, Sepultura, with the drummer-singer Dédé, ex-guitarist of the group Massacra Noise. The band used to play in the Hainaut region, in Metal cafes.

In October 1996, the band recorded their first demo: "The Forces Of The Night", containing 5 tracks, which sold to fans and also released an official video. of their concert at the Electric Ballroom.

The group turns into Thrash / Death with the arrival of singer Jean-Yves, who now replaces Dédé, who devotes himself entirely to drums. With a cavernous voice, similar to that of the singer of the time of the band Kataklysm. The group's texts become gory stories.

In 1997, the band welcomes a new guitarist, Gabriele Cassano, who becomes the second rhythm guitarist, composes new songs and takes a role of "backing vocals", in addition. It was also around this time that drummer Dédé was forced to leave the band for personal reasons.

The drummer is replaced by the young drummer Olivier Galuppo, being in the same spirit of the evolution of the group, a Brutal Death Metal with Thrash Metal and Black Metal influences. After some time, the members of the group having signaled to the singer that they would like his voice to clear up slightly so that we can distinguish the lyrics from the texts and sound less Grind Core, he tries some tests but he does not. does not succeed. He then definitively joined the Grind Core group, Mucus, with Anthony Gilles on drums, the first guitarist of Undertakers, and therefore of Katassamalass. Gabriele will also join the group Mucus as bassist.

Gabriele takes over the main vocals of the group and Anthony helps him with "backing vocals". The group saw the passage of several bass players, including notably their friends Karl Penning and François Lambert, but who did not correspond to their expectations and nevertheless decided to record their first demo, in November 1998, which they called "Extreme Brutality". , Gabriele will record the bass in addition to the vocals and the rhythmic guitar. This demo was a small success and the band performed in places like Magasin 4, Frontline, as well as various concerts in Metal cafes in the Hainaut region. The band then decided to compose new songs and record a second demo called "Mutilated penis". Having become friends with Black Metal band Svartkrist, the band decides to record a split with him at a studio in the Brussels region. This one will be released under the label "Painkiller".

After various conflicts between their musical tastes, the rest of the group wanting to evolve into a more brutal and gabriele grind core, being the main composer, decide to leave the group and stop "Katassamalass". The group is under the management of Nikki Neyah, who plays the group in Death Metal festivals with the groups: EXHUMATOR, DISJONCTOR, SERIAL BUTCHER, LOGGERHEAD, PUNISHMENT.

The project was reborn in 2006, by the decision of Gabriele, to continue the project solo, so as to compose the style of pieces that suits him and keeping the style of the old pieces but evolving in melody and technique, while remaining brutal and keeping the same influences. He then decides to record the album "Extreme Brutality", covering all the songs that were played while he was part of the group, also in homage to the musician who contributed to the birth of "Katassamalass"; without dispute from the former members of the group, because he wrote most of the songs and the lyrics. The project will be solo studio albums, with collaborations.