Agatus was formed in Athens, Greece 1991 by Eskarth the Dark One (lead vocals, guitars, bass, keyboards) who was soon joined by his brother Archon Vorskaath. Both are also members of the band Zemial which is more Vorskaath's project, while Agatus would be Eskarth's. Rehearsal tape in 1992 was the first, unofficial recording. In 1993 their debut demo "Night Of The Dark Ages" was recorded at the Molon Lave studio in Athens. The demo had three songs in the traditional Hellenic black metal style.