Overview
Meg Masters is a fictional character on The CW Television Network's drama and horror television series Supernatural. Created by the series' writers to develop a story arc for the first season, Meg is an unnamed demon who assumes the name of the host she possesses and begins antagonizing the series protagonists Sam and Dean Winchester. Nicki Aycox portrays her in the first season. Meg returns in the second season, possessing Sam and as such, was played by Jared Padalecki. The writers wanted Aycox to reprise the role in later seasons, but ultimately cast Rachel Miner for storyline purposes. Miner's incarnation evolves into an ally of the Winchesters and the angel Castiel over the course of the sixth, seventh, and eighth seasons.
In season 15, the entity known as the Empty assumes Meg's form to communicate with the Winchesters and Castiel.
Plot
Upon possessing a young woman named Meg Masters (Nicki Aycox), the demon assumes her name and tracks down series protagonist Sam Winchester in the first season episode "Scarecrow". The two briefly meet while hitchhiking—Sam left his brother Dean to track down their missing father John—and then again at a bus station. Despite her attempts to convince him otherwise, Sam eventually leaves to help Dean with one of their supernatural investigations. Meg slits a man's throat and uses his blood to communicate with her father Azazel, the demon responsible for the death of Sam and Dean's mother. Sam encounters her again in the episode "Shadow". Finding her reappearance suspicious, Sam spies on her and realizes that she is responsible for recent deaths of natives from his hometown. The brothers confront Meg and learn that the murders were actually a trap set for John, who has been hunting Azazel. After Sam and Dean reunite with John and acquire the demon-killing Colt, Meg begins killing their friends in "Salvation" and threatens to continue doing so unless they surrender the weapon. John delivers a fake gun, but Meg and her demonic brother take him hostage after quickly realizing the deceit. Meg tracks down the brothers in search of the Colt in the season finale "Devil's Trap", but is ultimately captured and exorcised to Hell.
Meg escapes Hell in the second season and takes possession of Sam (Jared Padalecki) in "Born Under a Bad Sign", seeking revenge against the Winchesters.
From Wikipedia (CC BY-SA 4.0).