One Piece: From the Rocks Era to King of the World - Chapter 400 - : Chaos in the World

Lady Bertia, who’s become my fiancée, is a bit odd. On our first meeting, she proclaimed herself a villainess noble girl who’s been reincarnated and said that she’s working hard every day to become a splendid flower of evil that’s elegantly put in her place.

I don’t get it.

But she entertains me because I don’t understand.

That’s why I think I’ll observe her for a while.

This is a story of a crown prince who’s so talented and handsome that he’s grown bored of his easy-mode life. A story of this prince observing a self-proclaimed villainess noble girl (who seems perfect at first but is a bit off) who’s become his fiancée as she snatches flags and breaks them into pieces.

Reborn into the Marvel world and become the son of the boss Jin Bing, what about the prince of the underground forces?

Don’t panic, the Black Shadow Corps provides the most loyal subordinates!

Twelve spells give you extraordinary power!

The eight demons will let you master the supernatural powers of overturning rivers and seas!

If you want to challenge, line up and come one by one!

- Description from novelbuddy

“Gu Hangshen! Your sister stole my man, and you helped her do it! Your whole family is rotten!”“Whatever my sister owes you, I'll compensate you.”“And what will you compensate me with?”“Me.”“...”Later, he not only gave himself up as compensation, but he also came with a clingy little bundle of joy...

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.