Who is Charles Mackey from The Midnight Club and what is their importance?

Charles Mackey is a deputy commissioner with the police department. It is also Mackey, who organizes a group of rogue cops in order to mete out justice where they believe the legal system fails. Mackey believes that certain criminal figures are untouchable, so he sends the group out to kill them. Isiah Parker becomes a member of the group because he believes that they can help him get justice against the man who killed his brother. When Isiah Parker finds himself set up and a target of these same men, however, he comes to the conclusion that he is making a mistake. Isiah Parker goes to Stef and helps him catch these criminals the right way.