16. Shane Walsh
For its first two seasons, The Walking Dead didn't have "villains" per se, aside from the shambling hordes of flesh-eating walkers and the occasional murderous ravager. The closest Rick came to an actual nemesis was his former colleague in the King's County Sheriff’s Department, who took care of his ol' buddy's wife and son when they all thought their man was dead. Unhappy at being usurped, Shane (played by Daredevil's Punisher himself, Jon Bernthal) consistently undermined his friend at every turn, becoming the first ongoing TWD character to insist that the only way to make it in this new world is to leave all scruples and sentiment behind. And love him or hate him, his return as a walker remains one of the series' more memorable moments.