Chelsea O'Bannon

Chelsea O'Bannon is married into the Rayburn family rather than born to it, which gives her a clearer eye on its dysfunction than any of the siblings have. She runs the marina business alongside her volatile husband Kevin, keeping the books and her temper in better order than he does, and watches the family's old wounds start to reopen with the wary attention of someone who married in, not up.

Sevigny plays her as the one adult in a house full of grown children acting out — practical, a little weary, never raising her voice even when everyone around her is raising theirs. The writing uses her as a barometer: when Chelsea gets nervous, the audience should too. It's a quiet, thankless role that she makes essential simply by refusing to overplay it.