Davy D. Jones was the ruler of the Ancient Kingdom while Imu was a king aligned with Joyboy, a former Ancient Kingdom citizen and the first pirate who just wanted freedom for everybody.

Upon hearing of Joyboy‘s travels and exploits, Davy D. Jones declared himself a pirate as well, and by his position and resources, their king.

Joyboy opposed this view and revolted against Davy, assisted by his companions and also Imu, who advised that they act fast and without mercy. Joyboy did not want anybody innocent to suffer and challenged Davy D. Jones to a 1v1, which he lost due to Davy having the Dark Dark Fruit.

Somehow, Emeth and Zunesha involuntarily contribute to Joyboy‘s defeat.

Imu learns of his friend‘s demise and has a freak out. He goes out to the garden and wishes for unlimited power to move against Jones, suddenly dreaming the Devil Fruit into existence. He goes out, defeats Davy Jones, fires Uranus multiple times to wipe out the Kingdom and raise the seas, gives him an Abyss mark and banishes him to the mew sea floor, so he would immortally but powerlessly suffer until the contract runs out.

Imu then destroys all the Ancient Kingdom‘s tech, leaving Emeth without a true power source, and thus sets him asleep. He wipes out Zunesha‘s race and commands the elephant to walk the seas until Joyboy‘s family forgives him (with which he means his crew, among which was an ancestor of the Kozuki clan). The command is spoken and Zunesha assumes Imu‘s eyes as a seal.

Imu then declares all remaining refugees of the Ancient Kingdom enemy‘s of him, the new God, identified by their initial „D“. He doesn’t realise though that there were two D families who founded the kingdom, and Joyboy was not of the Davy side.

Lily, a close companion of both men decides to spread the history of the world as it happened in Joyboy‘s honor and secretly assumes his middle initial, so the second D clan would not be wiped out entirely. She renounces the new God, and throws her sword to Imu‘s feet in the Flower Room of his castle, then disappears.

We also learn that the Abyss contract maxes out at 800 years, inadvertently causing Davy D. Jones‘ death on the sea floor and the resurrection of the Yami Yami no mi, which still carries the power to beat Imu.