In chapter 1138, there is a mural that started countless theories, also Harley added some context to it with three texts. One of the most interesting part of the first is one about enraging the god of earth and engulfing world with death and darkness. The texts tells us about slaves praying to the Sun God and Mural shows us people descending into something that look like a mineshaft. I think that rulers of the first world were mining resources and in their greed and hubris, they mined to deep or to excessive and they've caused eruption of supervolcano. Toba Supervolcano eruption caused massive extinction, it happened approx 74 thousands years ago. It caused death also ashes and sulfur dioxide block out sunlight and changed the climate. First World was destroyed by "natural" disaster. Humanity somehow survived that catastrophy and rules of world were changed.