As The Walking Dead fans know, sometimes zombies aren't your favorite character's biggest problems. The show and the comics have plenty of bad guys who are neither dead nor undead — and the series has just cast a big one. Jeffrey Dean Morgan, whom you might know as poor, poor Denny on Grey's Anatomy (or the worst dad ever on Supernatural), will be playing Negan, the villain who loomed large in The Walking Dead comics. Morgan will appear (probably) this season, and is expected to continue causing trouble in season 7. Even if you have no strong feelings about another antagonist being thrown into the mix, Negan's addition has some interesting implications for the fate of Glenn. While fans are busy creating any number of ways Glenn's untimely demise was all a misunderstanding, if the show is following the narrative of the comics, it's likely Glenn isn't dead — yet. He's offed by Negan in the comics, meaning Negan's introduction could signal a (temporary) reprieve. So, Negan probably won't be anyone's favorite character. But at least this casting news keeps hope for Glenn alive.