Katahane no Riku - Chapter 18.Rook Barusak

Everyone in the City of Jing thinks that bestowment of marriage between Xian Junwang and the daughter of the Yi’an Marquis House is to insert a fresh flower into manure.

On that day, the fog blocked everything.

On that day, he became the captain of a ghost ship.

On that day, he stepped through the thick fog and confronted a completely subverted and fragmented world—the old order had vanished, strange phenomonoms dominated the endless seas beyond civilized society, and isolated island city-states and fleets of ships challenged the sea that had become the last ember of lights for the civilized world. All of this while the shadows of the old days were still stirring in the deep sea, waiting to to devour this world that was about to die.

But for the new captain of the ghost ship Vanished, there was only one question he had to consider first— Who knows how to drive this ship?!

- Description from Novelupdates

5 years after the world changed, the final boss appeared.