
I think the recent era of One Piece is post apocalypse, the WG and Celestial Dragons took advantage of the situation using the remaining knowledge what the remaining void era have right now to control the world. They have been searching the hidden weapon that have the possibility to save the world from sinking, is Oda implying that the Pluton is Noah's Ark as the other ancient weapons could control the ocean and the sky. Joyboy and the rest of remaining species are fighting against the 20 nations to stop their corruption while they created the Ancient Weapons to protect the world. Why would the Celestial dragons and the government allowed the slavery and racial discrimination, destroying every nation who are against them, it's because they are power hunger people who want to take the ancient weapons for themselves, to be Gods.
People with "D" in their names are must be the descendants of the first generation pirates. After Roger find out the truth, he left the message for the new generation of people carrying the "Will of D" before his death so they can look for One Piece to stop the WG and their radical reigns.
That's my theory.

Never I've been rooting a red flag seme but the uke is the reddest flag in the whole story. The chap 1 foreshadowing uke received karma for all his and his family shits they did to Heeseo family. He should have leave Heeseo alone and let him live peacefully without those toxic foster parents using him as cash cow to exploit. Bro is hypocrite, he didn't even put his mother in prison for the crime she'd done.
EDIT: I know grape is bad, but Taekyung's indecisiveness ruined his and Heeseo life. His mother should be imprisoned for murdering Heeseo's mother. If he was smarter like any decent ukes of manhwa, he would dumped Heeseo to therapy, left him alone to live in peace and send the murderer to jail without caring that is his parent, crime is crime. That's how he should show remorse not paying and giving child support, stalking and asking about Heeseo situation like some creepy old man just because he feel guilty not sending his criminal parent to jail. He deserves all the hate like any toxic red flag seme and uke. Heeseo is by no innocent and actions are not excusable but he is a victim of sh*tty people, Taekyung, the foster parents, and Taekyung's mother. Let them hurt each other, each have consequences of their own actions.
If Martha and Henderson married, it would be wholesome family ╥﹏╥