Toaru Majutsu no Index: Genesis Testament - Volume 4, Chapter 3: The Counterattack Begins – Boy_not_“Dark”.

It’s said that the prince of virtue had almighty martial arts. It’s said that the prince of virtue had the most handsome appearance in the world. It’s said that the prince of virtue was brilliant. But all was legend! A fire ruined his wonderful appearance and his legs. Even the talented bride under their marriage agreement were replaced furtively. Ye Liu-li was his bad-luck substitutive princess. She went a long way to graduate from Medical University and had her internship with pain and joy. Who knew that in order to save a suicide patient, she fell off the building and crossed time into a “chessman” of prime minister. She had also been married to the disabled prince replacing her elder sister. On the wedding night, when most other couples were having their romantic night, she was thrilled. It didn’t matter. Revenge never came too late. She would never let go of any of them who entrapped her or harmed her.

Where there is light there shall be darkness

Hero? Nahh I'm the demon.

In a world where the demons are looked on as the incarnation of evil, the human-demon war raged on across the whole continent.

The Seraphims, protector of humanity, and the Demon lords who rule across all demonkind. Amidst all the chaos, Simon was reincarnated as the lowest ranking demon noble.

A brutal world where the strong feeds on the weak, eat or be eaten, kill or be killed. A demon far off from humanity….a dream unfulfilled in his previous life will be achieved in this life. Taking on the moniker of Laplace, he destroys all his enemies and rise over them.

This is a story of the flesh pushing everything.

In the Great Ye Dynasty, darkness descends, full of evil spirits and ghosts, killing invisible.

In the face of demons and evils, ordinary people can only shiver, curl up in the corner, and wait for their lives to come to an end.

Jiang Dao came through, carrying a martial arts modification system, and any martial arts can be modified infinitely as long as he glances at it.

The mad magic stick method, the eagle claw iron cloth shirt, the poisonous sand palm, the violent ape magic… are all revised to the realm of a thousand years later.

Facing the evil spirits, Jiang Dao had a burly body, muscles all over his body, and his eyes were like electricity.

“Evil spirits? Who said martial arts can’t kill evil spirits?”

- Description from novelbuddy

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.