His Role On The Walking Dead: Wilson joined the series at the beginning of its second season as Hershel Greene, the stubborn farm owner, holy man and veterinarian who saved Carl's life. He remained in the role through to the fourth season, becoming the heart of the group even as he lost his farm and foot along the way until, in "Too Far Gone," The Governor beheaded him outside the prison. His Role On The X-Files: In the seventh season episode "Orison," the series brought back serial killer Donnie Pfaster, who hadn't been seen since season two. Wilson played the titular Reverend who helped Pfaster escape from prison in order to kill him, driven by the belief he was doing God's work and armed with the power of hypnotic persuasion. As he forced Pfaster to dig his own grave at gunpoint, the serial killer suddenly appeared before him as a demon, which caught him off-guard and allowed Pfaster the opportunity to kill him instead.