Maya Eshet as Meredith Walker -Banshee-
Meredith Walker is a banshee. Meredith is rather demure, and is a patient at Eichen House for being mentally and emotionally unstable. Her whole family is revealed to be dead, and her banshee status presumably lead her to being institutionalized at the hospital. Meredith first appears in Season 3, and was revealed to be ‘the Benefactor’ the de facto antagonist of Season 4, though her actions were a product of her unhealthy state of mind. Meredith first appears in Season 3 episode “Echo House”, when Stiles is checked in at the institution. Stiles comes up behind her when Meredith is talking on a disconnected phone about an impending ‘death’, saying “one of them is standing right behind me”, which Stiles overhears. In “Insatiable”, the Pack figure out that Meredith is a banshee by comparing her symptoms to Lydia. Meredith escapes and breaks in to the school but is saved by the Pack before she is drugged and taken back to the Hospital by Brunski. Scott, Stiles and Isaac take her to Scott’s house. They hope for her to help them find where Lydia is taken, whom Meredith calls “the red-haired girl”. Meredith had received a message that Lydia does not want them to look for her. She listens to a phone, and says “Coup de Foudre”. Scott translates her message as French for “Love at first sight”, the phrase Noshiko Yukimura had taught her lover Corporal Rhys at Camp Oak Creek in 1943; Lydia is at Camp Oak Creek. Meredith is then presumably sent back to Eichen House afterward.
In Season 4, Lydia and Malia decide they need help from Meredith in “I.E.D.” to decode the other two thirds of the Dead Pool. Meredith heads to the high school, but is brought to the sheriff’s station by Parrish, saying she’s looking for Lydia. Lydia and Malia arrive and they ask her about what she knows. Meredith is cryptic and aloof as always saying Lydia ‘called her’. Parrish offers input that perhaps what she needs to tell Lydia may be a number to call. Meredith affirms this reciting the number 2-4-3-6. Lydia says a phone number is ten digits, but Meredith repeatedly insists that’s the number. Malia and Lydia later figure out the number sequence spells out AIDEN on a telephone pad, cracking the second third . In “Orphaned”, Lydia and Stiles pay Meredith a visit at Eichen House where they implore her to reveal the final cipher key. Meredith is shaking in fear saying things have changed, though she telling Lydia she wanted to help. Lydia asks Meredith why not help now. Meredith says ‘the Benefactor’ doesn’t want her to tell them. They ask Meredith for his name, but eventually she lets out a banshee scream giving Lydia a bleeding ear. When Lydia decodes the final third of the Dead Pool, she sees Meredith’s name and Lydia immediately has Parrish check on her. Unfortunately, Meredith had apparently committed suicide by hanging herself out of fear for her life. Her corpse is found by Brunski and Lydia and Stiles mourn her death. In “Weaponized”, Lydia claims a box of Meredith’s possessions and finds a photo of Meredith standing in the study of the Martins’ lakehouse. Lydia learns about the history of her grandmother Lorraine Martin and that Meredith was one of her subjects brought in for her study of parapsychology; Meredith had put on headphones for a test. Her ears bled out causing her to be hospitalized for a year.
In “Perishable”, after Brunski dies from being shot by Parrish to save Stiles and Lydia at Eichen House, Meredith reveals herself to be alive, she had been using Brunski because she knew of his being a serial killer, and says, “(Brunski) wasn’t on (her) list.”: Meredith is revealed to have been ‘the Benefactor’ all along. She’s brought to the sheriff’s station. Lydia implores Meredith why would she launch the Dead Pool. Meredith tells Lydia she only wanted “to help” and also wishes to only talk to Peter Hale. When Peter arrives, he repeatedly tells Meredith they have never met. Meredith says he doesn’t remember her. Peter reacts to this, initiating a mind meld. Through Meredith’s memories, its revealed during her hospitalization from Lorraine’s research, she was placed next to Peter when he was comatose from the Hale Fire for months. The whole time, Meredith could hear Peter’s thoughts telepathically: Peter was ranting in response to his trauma from the fire, raving over how he’d predicted the Argents would target his family. Meredith was terrorized by Peter’s cognizant revenge-fueled thoughts that he would remake the supernatural of Beacon Hills in his image instead of his sister Talia’s. To do this, Peter had said first he’d hire assassins to purge Beacon Hills of supernatural people, placing them all on a hit list, “The Dead Pool”. Peter was originally the one who planned the Dead Pool, though he didn’t remember; Meredith, using Lorraine’s computer code to comprise the Dead Pool, put the list online. Lydia talked with Meredith afterward, the latter justifying Peter’s ‘plan’ in that the supernatural are monsters, even them the banshees. She believed too many people have died because of them, and that she decided “to help”: she enacted the plan in response to her ‘hearing’ Lydia Scream as Allison died. Lydia tells Meredith “not all monsters do monstrous things”, like Scott. Meredith touches Lydia’s face and realizes, also like Lydia herself. The vulnerable, brainwashed banshee sheds a tear showing remorse lamenting “What have I done?”