Filii Nigrantium Infernalium is an old school black metal band from Portugal. João Pedro from Moonspell played with them too, here he was called Tetragrammaton another well-established musician from the Portugese scene that played with them was Luís Lamelas (known for his works in Moonspell, Desire, Millennium etc.). Just a few releases were done so far. The first few years the band was called Bactherion. (Source: F.S.)