Billy Ross

Billy Ross is one of the county detectives pulled onto the Erin McMenamin case in Easttown, working alongside Mare Sheehan's small-town resentments and jurisdictional friction. Practical and a little overshadowed by his more eager partner, he goes about the unglamorous work of the investigation—interviews, legwork, paperwork—without much fuss or self-regard.

Robbie Tann plays him as procedural furniture at first, which is exactly the point: Mare of Easttown is full of people doing ordinary jobs inside an extraordinary grief, and Billy's steadiness gives the frantic, personality-driven parts of the investigation something dry and grounded to bounce off. He never asks to be noticed, which is why he is.