Bu Sha - Volume 1, Chapter 7 : Dragon’s Contract

Frank, a mercenary known for his cold ruthlessness, decides it’s time to leave the bloody world of the underworld behind. But the underworld has no plans of letting him go. Relentless enemies from his violent past keep hunting him, and eventually, they succeed—Frank is killed.But fate has other plans. Instead of staying dead, he is mysteriously reincarnated into the body of a cop in a world filled with crime, corruption, and dark secrets. With the help of a strange, all-knowing system, Frank is given the chance to live again—this time, to prevent crime before it happens.

Son of a bitch! I just finished this godawful fantasy novel, and now I'm knee-deep in it – as David, the disgraced son of the Solarian Empire's top general! Talk about some twisted cosmic joke. But hold on a damn minute... maybe this isn't all bad. Armed with the knowledge of that trashy plot, I can become the ultimate shadow player, an overlord perhaps. Screw the damsel-in-distress harem too – it's time to pull the strings and become the real power behind the throne. This isekai might be a steaming pile, but I'm rewriting the ending with a little more... Debauchery (wink wink).

A Count’s Daughter who lost in the running to become the Second Prince’s fianceé, Camilla. The Prince chose a Baron’s daughter as his fianceé, and the world blessed the two’s love as fated. On the other hand, Camilla who was tailored and elevated as the love’s villain in the end, as punishment she was made to marry a terribly fat and ugly man――called『Toad of the Swamp』from his appearance, a lord of a remote region named Alois.

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