Around 1,000 year ago, the Axial Age was at its height. The cultures of the Yan Ki, Northmen, Phoenicians and Early Men reached maturity, right as the Cyclops civilization began to fall into disarray. Such high cultures could agree on one thing, slavery at the hands of the Cyclops could no longer be tolerated.
The center of Cyclops civilization was Redstone Island and the region most contested was the bogs of the Three Valleys region. Here, the Early Men made their home and the Northmen held sway. The Cyclops were hindered by the mountains protecting the Three Valleys, which made it difficult for them to defend it. Thus. many battles were fought here and the Cyclops made it a point to leave their mark so there was no confusion who was in charge.
Dozens of Cyclops standing stones were placed in the bog region, a show of their power, but otherwise not of magical significance. It's also said, the Cyclops lich, Thunderer, made his home somewhere in the valley region. Undead began appearing shortly thereafter, to the point nobody has ever survived the night in the open in the Three Valleys.
Towards the end of the Axial Age, the Battle of Three Valleys took place. The Northmen General Habgard had build a wall defending the region from the Cyclops. The Cyclops breached the wall, defended by the Northmen and Early Men warriors. In an act of betrayal, the Northman leader now known as Bloody Erik, allowed the Cyclops through to decimate his Early Men allies. He believed The Northmen would one day take Redstone Island and eradicate the native inhabitants, a view that it was later learned he received from his spiritual guide, the Cyclops lich Thunderer.
The Three Valley region remains in turmoil today. Slavers and goblins harass the Early Men tribes. The Early Men civilization is long gone and they hide in the cracks of the earth from their enemies. Undead run rampant through the region, with different groups acting in different ways. Those in the north of the region only come out at night, killing and dragging off their victims. Undead from the south rampage at all hours, often kidnapping who they find. The red dragon, Flameworm, considers everyone in the valley a trespasser, including the forces of Crannog. The druid Pholus works to maintain a balance, although his feud with Flameworm often keeps him gone for long periods. It is the chaos of the Three Valleys that keeps Tara safe from invaders from the east of the island, but that safety may end one day soon.