Asura: The City of Madness (2016)

Detective Han Do Kyung, who for years has been secretly doing dirty work for the corrupt mayor Park Sung Bae, is now pressured by a ruthless prosecutor Kim Cha In to cooperate in an investigation against the mayor. Feeling trapped, Han persuades his young partner Moon Sun Mo to take over his work for the mayor, but things start to get tangled in unpredictable ways. As things are getting worse, only the evilest survive in this dog-eat-dog world.