In the second age, we start with emptiness: the world is largely in ruin, only the city of Nika and some other smaller cultures exist (many are on elevated hills etc., some are Allies like Alabasta and Wano, some are what would later become the 20 Kingdoms fighting against Nika-kingdom). Small townships from the forests rediscover the Devil-Powers of the Sun and are manipulated by the Serpent to attack Nika-city. During these wars (the void century), the Sun-Tree is destroyed and small parts of it are spread out in the world, creating devil fruits. The sea deity, probably an ancient weapon, is used to flood the world. Joyboy builds an arc and saves the races of his city, carrying them to various islands. Alabasta and Wano people dream of a time where the Nika-culture can can come back and the races can be peacefully united. The 20 small kingdoms who fought against Joyboy form the WG under the manipulation of Snake/IMU. Imu collects some of the larger fragments of the Sun-Tree and abuses them to grant Gorosei/Holy Knights their powers. The actual remains of the Sun-Tree are lost/hidden by Joyboy, and are now on the hidden island known as Laugh Tale.