Who played Rick Grimes in 'The Walking Dead'?

In which TV series is Elena Gilbert a main character? Who played Damon Salvatore in 'The Vampire Diaries'? In which TV series is Damon Salvatore a main character? Who played Richard Castle in 'Castle'? In which TV series is Rick Grimes a main character? Who played Daryl Dixon in 'The Walking Dead'? In which TV series is Daryl Dixon a main character? Who played Negan in 'The Walking Dead'?