The Great Flood is a catastrophic event in 140 AG that destroys many of the factions on continental Hyrule and leads to the events of Great Sea: Total War. Though Hylia manages to destroy the artificial moon created by Major before it strikes Hyrule, the gravitational effects of its pull and the rain of falling orbital debris devastate the world, causing massive flooding along Hyrule's coasts that drown entire cities and nations beneath the waves. Though the floodwaters eventually recede, the catastrophe leaves Hyrule a shattered land and forces its surviving peoples to look north to the Great Sea for new lands and resources.
Few organized groups survive the Great Flood. The Kingdom of Hyrule and Lanayru Province survive and unite as New Hyrule, and retain their status among the dominant old-world powers. With their homelands in ruins, many peoples such as the Gerudo, Ordonians, and Labrynnians assimilate into the Kingdom of Hyrule or depart for new lands. The few surviving Kokiri, with their homeland destroyed, complete their transformation into Koroks and depart north into the Great Sea to establish new. Likewise, the remaining Moblins are united under Vaylonon, a Moblin claiming to be Ganon's daughter, and construct a fleet to join their Ocean Blin cousins in the northwestern Great Sea. The Darknut Legion also manages to survive in some capacity, isolated from the mainland by the inundated Gerudo Desert.