The First Ruin was a calamitous event deep in Eamon's past that marked the beginning of the Ages of Ruin, a protracted dark age during which hordes of undead creatures and other monstrosities would periodically emerge to ravage the world and cripple its civilizations.

Legends say that a warrior called Nuorgam (a name meaning "Northman") arrived in southern Addar and using the magical Sword of Inari liberated the humans living there from the monstrous servants of the slumbering Great Old Ones. The freed people united to create the Tasavalta, the first human republic.

Two centuries later the evil and undead creatures of the region returned in force, stimulated by the dark energies of the Great Old Ones who were now stirring. With Nuorgam gone and his sword missing, the defenseless Tasavalta was overrun, its people slaughtered, and the very land itself shattered and made to sink into the sea. The old gods soon returned to their slumber and the few bruised survivors fled the region.

The destruction of Tasavalta marks the first recorded instance of what is now known as the Cycle of Ruin, periods of catastrophic destruction that would occur every 2,300 as the Great Old Ones followed their slow rhythm of sleep and wakefulness.