Potential spoilers for The Walking Dead and major spoilers for The Walking Dead comics ahead
With the recent introduction of the Oceanside community, The Walking Dead is certainly advancing some parts of the original timeline from the comics. The show was obviously never a perfect match to begin with, and it will likely diverge from the timeline further in the future.
One thing that this could mean is that the Whisperers end up being introduced much earlier than they were in the comics. In fact, this has already been teased a few times by the producers when asked about the group, and some fans have speculated that the mystery figure seen in the post-credits scene of The Walking Dead's midseason finale was a member of this new faction. If you're not that familiar with the comics, though, you might be asking yourself: Just who are the Whisperers, anyway?
They Whisper and the Dead Don't Mind
In the world of The Walking Dead, some people do whatever it takes to survive. We've already seen Rick and company cover themselves with the scent of walkers to escape from potentially deadly situations, and it's very likely that they're not the only ones out there who know this little trick. In fact, there are some survivors who take it much further than Rick or his friends have likely ever considered.
The Whisperers are a group of survivors who actually wear the skin of walkers that they've killed so they can go about their business without being harassed. The skin is cleaned, stretched and processed like leather, preventing the Whisperers from catching diseases from it, but it is still sufficient to mask their scent and make them smell like they are dead. They move freely among the dead, adopting the same sort of slow movements that walkers use to keep from attracting attention to themselves. When they speak they speak in whispers, only loud enough to be heard but not loud enough to draw attention to themselves. Between the flesh of the walkers and the slow and quiet movement style, the Whisperers have nothing to fear from the dead.
The living is another story, however. The Whisperers view themselves as animals within a pack, and are very territorial. They know that others might not accept their ways, and are more than willing to kill trespassers onto their lands. In the comics, they marked their territory after Rick and his group crossed into it by killing several characters and placing their heads on pikes.
Alpha and Beta
The leader of the Whisperers is Alpha, a bald woman who is first introduced when she confronts Maggie and the other survivors living in the Hilltop community about her captured daughter Lydia. She proposes a trade, offering to free two of the survivors that the Whisperers captured in exchange for Lydia. Despite being Lydia's mother, Alpha does not allow the girl or anyone else to use her real name; throughout the comics, she is only addressed as "Alpha" so her identity before joining the Whisperers is unknown.
Alpha's second-in-command is Beta, a large man who is notable in that his skin mask only covers the top portion of his face. He is very protective of Alpha, offering to kill anyone who dares lay a hand on her. His devotion to her leadership is total, and he has no aspirations to rise to her rank. When she is killed in the comics, he insists that neither her killer nor he himself will be known as "Alpha" in her place... the Whisperers will not have another Alpha. Instead, he states that they will continue to follow Alpha's commands... and since the other communities had trespassed onto their lands, they must all die.
Lydia and Carl
Lydia is placed in a cell in Hilltop after she is captured, held next to Carl (who was locked up for accidentally killing one of two boys who attacked Maggie's daughter). Lydia and Carl begin talking, eventually forming a strong bond. Carl ends up giving her his hat to help build her confidence that she doesn't have to be the strongest to survive, and she asks to see underneath the bandages that covered his missing eye. She tells him that the wound is "sexy", and the two begin a somewhat strange relationship.
When Lydia is released to the Whisperers, Carl follows them to make sure that she's alright. He stays among the Whisperers briefly, until Alpha disowns Lydia for a display of emotion that she considers weak. She sends Lydia back to the communities with Carl, though she also secretly informed Rick of this to ensure that Lydia would be protected and taken care of. Carl and Lydia remain close, and their relationship continues to grow as she moves first to Alexandria and then back to Hilltop to keep her safe.
Before she was released to the Whisperers, Lydia took Carl's virginity and commented about how it was much nicer than previous times that she had been with someone sexually. Carl realized that despite being Alpha's daughter, she had been raped multiple times among the Whisperers. He tells her that what they had done to her wasn't okay, and as her trust in him builds she slowly learns to respect herself more as a person. He is loyal to her and wants to protect her, and she finds a home at his side like she had never known among the Whisperers.
Negan and the Whisperers
After a major war with Negan in the comics, a two-year time jump occurs and the story picks up with civilization being rebuilt. Negan is still alive at this point, though he was captured after the final battle. Not everyone is happy with the way that things are going, however, and Negan is broken out of his cell so that he can go to the Whisperers and convince them to attack Rick and company. Negan agrees, though he double-crosses his patron and leaves him dead at the Whisperers' border as he makes his own way to the enemy camp.
Once he meets Alpha, Negan immediately begins hitting on her. Despite Beta's objections and desire to kill Negan, Alpha keeps him alive and actually seems to warm to his affections. Negan could never actually be at home among the Whisperers, though, as rape is a part of their culture and it is one thing that he cannot abide. He is left alone overnight as punishment for intervening in an attack, but Alpha comes to talk to him. He opens up to her about his past, and she tells him that he might belong there with her after all. Unfortunately for Alpha, he reveals that he doesn't actually want to belong there as he slits her throat and cuts off her head to take back to Rick.
The Whisperers War
The Whisperers end up being a fairly major recurring enemy in the comics, with the last several story arcs being dedicated to a conflict with the group. The Whisperers attack in the wake of Alpha's death, as the combined communities unite to take on their threat once and for all. One group of Whisperers seek out Lydia to inform her of her mother's death and bring her back into the fold; she tells them in no uncertain terms that she's not coming back, however, killing the Whisperer who tells her to come back.
The war with the Whisperers is still going on as of this writing, so it's unclear whether the group will be wiped out by the end of the arc. Even if they are, it's possible that some other group will adopt some of their tactics as a means to survive. Should even some of the Whisperers survive, though, it's all but a given that they'll return to plague Rick and the other survivors at some point in the future.