Helen

Helen is the assistant district attorney assigned to prosecute Nasir Khan for the murder that opens the series. She is methodical and unglamorous, treating the case as a matter of evidence and procedure rather than spectacle, and she approaches the young man's guilt with the calm certainty of someone who has done this job for a long time.

Jeannie Berlin plays her without a trace of courtroom theatrics, which is exactly the point: Helen's menace is her competence. The show could have made its prosecutor a villain, but instead gives us a tired, sharp professional convinced she's right, and that quiet conviction is far more unsettling than any performed cruelty.