The Walking Dead has featured many memorable villains over the years, but the original was Shane Walsh, as played by Jon Bernthal. He and Rick Grimes used to be best buddies, but once Rick woke up out of his coma following the apocalypse, tensions immediately ran high between them. Shane had started up a romantic relationship with Lori Grimes and the pair fought it out to be the alpha male of their group.
In season 2, Shane went off the deep end when he began killing others, including sacrificing Otis to save his own skin and executing Randall, a prisoner, even though everyone had agreed to spare his life. He eventually led Rick out into the woods to kill him, but Rick managed to turn the tables. Shame then reanimated and was put down by young Carl. This happened in the penultimate episode of the second season.
According to creator Robert Kirkman, however, Shane was supposed to die at the end of season 1. Had AMC ordered the expected 13-episode debut run instead of a limited six, Shane would’ve been killed off in the first year before the group moved on to the farm. This would’ve massively changed events, as someone else would’ve had to have stepped into an antagonistic role, killing Otis and Randall and being an obstacle in the search for Carol’s daughter Sophia.
Instead, Bernthal got to stick around until the end of season 2. He later returned as Shane in Andrew Lincoln’s final episode in season 9, as an injured Rick hallucinated his old friend-turned-enemy, showing that murdering Shane still weighed heavily on Rick all those years later. Even though Shane is long gone, this cameo opens the door for another return, perhaps via flashback, in those upcoming Walking Dead movies.