Warning! SPOILERS for The Walking Dead season 10 & comics ahead.
The Walking Dead season 10 has revealed Alpha's biggest weakness, hinting that it won't be Negan who kills her but rather her daughter, Lydia. The Walking Dead TV show has never been against changing events from the comics books, sometimes even doing so in order to keep fans familiar with the comics on their toes. In this case, however, having it be Lydia who kills Alpha instead of Negan better fits the story the AMC series is telling.
This season of The Walking Dead finds the survivors in something of a Cold War with the Whisperers, both waiting for the other side to make a move. The moment happens in the season 10 premiere, when a crashing satellite and the resulting forest fire force the survivors to cross the border into Whisperer territory. It isn't the first time they've crossed the border, but this time Alpha finds out, spotting Carol on a ridge as the two share a climactic stare down. The Whisperer War is soon to begin, but already, the setup is differing from The Walking Dead comics.
In The Walking Dead season 10, episode 2, "We Are the End of the World", Alpha finds herself emotionally tested, and how she responds reveals a key weakness in her dedication to the Whisperer way of life. This weakness creates a strong argument for why it might be Lydia and not Negan who kills her, changing the story from what happens in The Walking Dead comics but also better suiting the narrative of the AMC series.
Why Negan Kills Alpha in the Comics
In The Walking Dead comics, it's Negan who eventually kills Alpha, but the TV show hasn't recreated those same circumstances which lead to Negan killing Alpha in the comics. This is partially due to the very nature of AMC's adaptation, where they incorporate original ideas and characters to the already established narrative, but in this case, Negan is unlikely to kill Alpha because of the absence of Rick Grimes.
During the Whisperer arc in The Walking Dead comics, Negan escapes his imprisonment at Alexandria and seeks out the Whisperers. At first, Negan joins up with the Whisperers thinking he can turn them against Alpha, assume leadership, and use them to get his revenge on Rick. It doesn't take long, however, for Negan to realize that isn't likely to happen, and the more he learns about the Whisperers, the more he's repulsed. In particular, Negan is disgusted by Alpha's refusal to intervene in the attempted rape of young woman by other Whisperers, with her believing that to do so only fosters weakness. Negan stops the assault himself but this leads to a huge argument, and upon learning that Alpha has even allowed her own daughter to be raped, Negan slits Alpha's throat and decapitates her. Negan brings Alpha's head back to Rick as way to earn his trust, and it's only after this, that Negan is slowly granted more and more privileges in Alexandria, even fighting alongside them in the Whisperer War - which begins in earnest following Alpha's death.
Negan's entire journey with the Whisperers is driven by his thoughts of Rick, first in revenge and then in seeking forgiveness. And while it's by no means impossible for AMC's The Walking Dead to recreate a similar scenario, their Negan has already experienced a transformation across season 9 wherein the residents of Alexandria have begun to trust him. Any motivation for Negan to kill Alpha now would need to be different, which is why in the case of The Walking Dead TV show, it actually makes more sense for someone else to kill Alpha.
Lydia is Alpha's Biggest Weakness
The Walking Dead season 10 episode, "We Are the End of the World", explores more backstory for Alpha, Lydia, and Beta. In doing so, it explains how Alpha and Beta came to form their strange partnership and create the Whisperers. But the episode also highlights the inconsistencies within Alpha, and how being a mother is the last piece of her humanity she can't shed. Loving her daughter is Alpha's one weakness.
On The Walking Dead TV show, it's very clear Alpha loves her daughter and she struggles to suppress those feelings in order to abide by her own Whisperer code. This disparity between Alpha's love of her daughter and her bleak world view is reflected first in the past, with flashbacks to Alpha keeping Lydia alive at all costs, and then again in the present, with Alpha trying and failing to forget her love for Lydia. When Alpha is attacked by the mother who she forced to abandon her baby last season, Alpha is saved by that woman's sister, who kills her in order to protect Alpha. Alpha later christens that Whisperer, Gamma, in a ceremony where she announces that "we're strongest when we kill our own." It's the same ways of thinking that led to Alpha ordering the mother to abandon her baby in the first place, but it's a way of life that even Alpha herself can't seem follow.
She lied to Beta and the other Whisperers about killing Lydia, and even though she appears to recommit herself to the Whisperer code by destroying that "nest", it almost certainly won't stick. Loving her child is the one part of herself that Alpha can't seem to lose. It's why instead of punishing the Whisperer mother earlier in the episode, she comforts her, sympathizing with the pain of losing a child. Doing so is also what allows for that same mother to later attack Alpha, already hinting at how any compassion is a weakness for Alpha. And it's why when confronted with Lydia again, Alpha won't be able bring herself to kill her daughter, again leaving herself open to attack - only this time from Lydia.
Why Lydia Will Kill Alpha on the TV Show
Lydia is a strong candidate to kill Alpha on AMC's The Walking Dead because as her daughter, Lydia is Alpha's one weakness. If anyone would be able to catch Alpha off her guard, it's Lydia. The Walking Dead is certainly trying to convince audiences that the deed will be done by Daryl or even Carol, but Lydia has just as much if not more reason to want Alpha dead.
Lydia is a victim of her mother's abuse, both verbally and physically. We see this both in how Lydia's childhood memories are twisted by Alpha, and in what actually happened once Lydia begins to remember things correctly. Alpha may love her daughter, but it's a controlling kind of love that doesn't allow for anyone else to share in it - including Lydia's own father, who Alpha murders shortly after the start of the outbreak. That alone is reason enough for Lydia to want her mother dead, but when compounded with the years of abuse, it's easy to see how Lydia has more reason than most to kill Alpha. Not only does Lydia killing Alpha make sense as an act of revenge for her father, but Lydia being the one to kill Alpha would also achieve what Negan killing Alpha did in the comics - gain the trust of the other survivors. Right now, many in Alexandria and the other communities still fear that Lydia is some sort of Whisperer spy. Killing the leader of the Whisperers would prove to many where Lydia's loyalties truly lie.
Having it be Lydia who kills Alpha instead of Negan is a more satisfying arc for where The Walking Dead season 10 appears to heading. Lydia as a character who is already more strongly developed than her comic book counterpart, and having it be she who kills Alpha, her own mother, allows Lydia to free herself from a painful past. It won't be an easy burden for Lydia to bear, of course, but in doing so, she can sever her ties to Alpha and the Whisperers and move on with people who will actually treat her right.
The Walking Dead season 10 continues Sunday, October 20th with "Ghosts" at 9pm/8c on AMC.