Potential spoilers below for The Walking Dead TV show, as well as the comic book series. If you don't want to know what Negan's fate is like in the source material, please check out one of our many other Walking Dead articles.
The Walking Dead is a series that rewards viewers who view episodes multiple times, whether it's with subtle nods to the comic book source material or seemingly innocuous moments that secretly hint at future events. Now that TV audiences have seen exactly what big bad Negan is all about - and it sure ain't pretty - we can start really thinking about how that son of a bitch is going to go down. And even though Negan's past and future actions are worthy of the most drastic retaliation tactics, the deadly antagonist's fate may have already been cleverly teased through Morgan's return to Alexandria last year.
When Rick and Morgan finally reconnected at the onset of Season 6, it was thought they might get along better than they did, considering their history, but Morgan was a far different person than he had been in previous seasons. He'd gone from half-mad to full-zen, in large part because of the patient lessons from John Carroll Lynch's short-lived Eastman. It's here that Morgan shifted his concept of survival and opened himself up to a similar form of rehabilitation from others (just as Eastman had done). He was so changed that he actually built a jail cell within one of Alexandria's homes. Morgan's story seemed very weird at the time, but it's now far more obvious that it was setting up the end game between Rick and Negan and the All-Out War arc on the way.
You see, in the comics, Negan does not win the war, which shouldn't come as a big surprise to anyone. And after a form of victory had been grasped, Rick made the surprising decision to not just kill Negan as had been done with so many others, but to keep him imprisoned within Alexandria, both to make him suffer through long-form punishment and to test the concept of rehabilitation on such a monstrous bastard.
That doesn't sound at all like the Rick Grimes we know from the TV show, but we don't know what's going on in his head all the time, and Morgan's words definitely had an effect on Rick (and Carol, if we're keeping count). Particularly when Morgan explained to Rick that the cell was built so that the community's citizens will have different choices the next time they're faced with threats, as pointed out by ComicBook.com. He was talking about the ambush-ready Wolves at the time, but the thought clearly extends to anyone who means to do other survivors harm. Such. As. Negan.
Considering Morgan has been gone from Alexandria since going on his Carol hunt, he hasn't been the sage angel on Rick's shoulder as the leader goes through the hardest defeat of his post-apocalyptic life. Not that Rick has been in a position to decide whether to kill Negan or not, but he will no doubt regain his confidence and justice-fueled bravado soon, perhaps in the next episode. As he plots and plans the eventual take-down of Negan's Sanctuary and its inhabitants, his vengeance will need to be quelled in some way, so it's good that he'll presumably be visiting The Kingdom soon, which will put him back in contact with Morgan.
There are obviously a thousand different ways that things could go down between now and the "end" of Rick and Negan's feud. Rick could slice Negan's throat. Someone could burn down the house with the jail cell in it. Morgan could reverse ideals and turn into Jack the Ripper. The Walking Dead has gone out of its way over the years to strike up differences between the comics and the live-action series, so this could all be a big gotcha by the time Rick & Co.'s victory is in sight. But on the other hand - and Rick only has one hand in the comics - it might go down exactly like this, with Jeffrey Dean Morgan spending a lot of his future performance time behind bars.
The Walking Dead will give audiences another super-sized episode for its midseason finale on Sunday night on AMC. Be sure to tune in, and don't forget to keep our midseason premiere schedule bookmarked so you know what's coming to the small screen in the near future.