Seth Ezekiel Cohen is a fictional character on the FOX television series The O.C., portrayed by Adam Brody. Seth is one of the "core four" characters on The O.C. alongside Ryan Atwood, Marissa Cooper, and Summer Roberts. Seth's friendship with Ryan, who eventually became his adoptive brother, formed a focal point of the series along with their romances. Seth married Summer in the series finale. His other relationships were with Anna Stern and Alex Kelly.