Asura: The City of Madness (2016)

Hwang Jung-min masterclass.
Noir crime thrillers.
Corruption.
Cops vs organized crime in New World, Cops vs corrupt mayor in Asura.

In both productions a bunch of dirty cops, riffraffs and prosecutors use unconventional methods to take down powerful and corrupted politicians. Both have lots of violence, although Asura is slightly bloodier.