The tags have been changed way too much. In short, this is a seafaring adventure story.
The Sea of the Dead contains many different seas: the Sea of Doors, the Sea of Dragons, the Sea of Night, the Sea of Mist, the Sea of Toys, and more. Each is different, and they will all be explored one by one.
Ai Wowowo died fighting a fish.
When he woke up again, he had arrived in an unknown sea.
This was the Sea of the Dead, the final resting place of the deceased.
The dead drawn to the Sea of the Dead would gain temporary physical bodies there.
Only by constantly absorbing new “energy” could they prolong this second life.
After coming to terms with his situation, Ai Wowowo decided to make the best of it.
He would use the Book of the Dead to recruit subordinates and venture across countless seas.
Then, one day, he would become an Eternal, no longer bound by the fleeting life of a physical body.
Author, don't give up