The God Valley

The manga introduced a new island, known as God Valley. Sengoku says it was wiped from the books of history. He also adds it was involved to the taboos of the world, meaning the Poneglyph and the Ancient Weapon. But we heard of that island before, it's the kingdom that Professor Clover talked about, which was wiped from history.

Professor Clover said the existence of the kingdom posed a threat to the world government, and while he wasn't sure why, they key to it was the name of the kingdom. The name is God Valley. This is because this island poses a threat to the living gods of the world, the Celestian Dragons. Someone normally would discover about the Poneglyph and the Ancient Weapon when they reach the island at end of the Log Pose. That island is God Valley. Rocks reached God Valley, and he decided to find the Ancient Weapons to become King of the World. It was after the God Valley Incident that Roger, Whitebeard and the others went on their own journeys. Shiki also said he and Roger would use the Ancient Weapon to rule the world. This is because he was a member of the Rocks Pirates, and is just following his former captain plan.