Great Dark War

The Dark War sometimes know as the First War of Magic, was an event that took place decades before Calamity Trigger. During the Dark War, mankind developed Ars Magus to defeat The Black Beast. The Black Beast spread seithr all over the world, as that was the only way the Black Beast could operate. The Black Beast's power was overwhelming, so mankind tried to do everything they could to eliminate the seithr, thinking it would be easier and safer than fighting the beast directly, but even that plan failed. Eventually, the Six Heroes appeared and the situation took a turn. The Six Heroes taught mankind the secrets of 'Magus'. And from there humans invented machinery that can utilize seithr as a source of energy. After the humans figured out how to use the Armagus, they fought alongside the Six Heroes and defeated the Beast.