Demon Lord City is a Manga/Manhwa/Manhua in english language, Drama series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

In the "Demon City" where humans and demons coexist, one of the seven demon kings is murdered.In order to solve the case, Alsarisa, the daughter of a hero who enforces justice under the law, teams up with Keed, a bad investigator who values honor over the law. In a world swirling with violence and conspiracy, the unconventional investigation drama of the two twisted people begins.