Arifureta Shokugyou de Sekai Saikyou (WN) - Volume 2 Chapter 6

A mental patient, or a born policeman?

A peerless genius, or a master of crime?

There are cops who are least like cops, and there are criminals who are least like criminals.

Neither good nor evil is absolute.

It is a grey world we live in.

- Description from Novelupdates

Dante was an ageless warlock who had been going from one battle to another for hundreds of years.Following a chaotic encounter with an evil god, Dante unintentionally activates a contract with a demon, thrusting him into the modern world.Resolved to live a peaceful life, his intentions are halted when he finds himself in the middle of a conflict among rival mafia factions—dabbling with the ominous demonic magic that he knows best.

Talent, appearance, power.

Sirens: a name derived from an ancient creature, used to describe those who could charm, lure, control, and heal others by singing.

Subjected to live the life of a siren, Aria had experienced, seen, and heard many horrific things. Broken beyond repair, Aria resigned herself to death, when suddenly…

The Grand Duke, Lloyd Cardence Valentine, arrived and whispered, “Should I kill everyone here?”

“If you need me, just call me. Your song will always reach me, wherever you are.”

In the end, Aria called the devil, bringing death to all those present, along with herself.

“Let’s fall down to hell together.”

And with that, Aria breathed her last and died… only to return to her 10-year-old self.

Now that she had a second chance at her life, Aria was determined to change her fate, as well as the cruel fate of her saviour, Grand Duke Valentine.

And so… Aria proposed to him with a marriage contract.

She sold her soul to the devil and vowed to protect him.

The young duke took the contract from her hand.

“So, where should I stamp the seal?”

* * *

“You said you’d divorce me within 10 years.”

The grown-up villain leaned in, hovering his head before he kissed her tenderly over her crown.

“Now that we’re adults, we should sign another contract.”