personally I think that Italian projects that fits in the "death industrial" umbrella started in the 90's with Atrax Morgue/Morder Machine, Today I am Dead, Dijin, No light of tomorrow, etc.
Before then there were mostly experimental projects, ritual/ambient, isolationist and power electronics/noise oriented.
In the 80's, until the early 90's, for sure MB, SODALITY, LAXATIVE SOULS, Giancarlo Toniutti, Bruno Cossano, early Ain Soph (although my fave records of them are definitely Kshatrya and Aurora), Sigillum S, Iugula-Thor (their first record THE WHEEL OF THE PROCESS is one of the best of those years and not only in Italy), etc.