Meg

Meg is a upper-level demon that trained under Alistair in hell. She is considered to be one of the Yellow-Eyed demons "daughters". She is responsible for the killing of Adam Milligan's mother, Kate as well as the killings of Jim Murphy and Caleb, two of John's friends. She first appeared when she met Sam after he had had a fight with Dean and briefly separated from him. Later, she appeared again when she was in Chicago murdering innocent people. She soon lured them into a trap-a trap that was meant for John, in reality. She revealed that she was the one to kill Kate, and tried to play with Adam's mind by telling him that his mother regretted ever having him, that he was a distubrance and that he wa sher worst mistake. Soon, though, the shadow demons that she was controlling, rebelled against her after failing to kill the Winchesters. She and her host body were thrown from a seven story apartment floor.

Around July 2006, she put into motion her next plan. She knew that John had the Colt gun-capable of killing all demons. In order to get the gun, she attempted to trap John. She went around killing many of his contacts and friends, notably Pastor Jim Murphy and Caleb. She called John and told him that she wanted the gun and that the killings wouldn't stop until he had given it up. When John played dumb, she immediately killed Caleb while he listened over the phone.

Agreeing to give her the gun, John, in reality, was giving her a fake gun. When he met her, she and her friend tested out the gun, only for it to be proven a fake. John narrowly escaped the assault. She is not seen again, though she is still working for Azazel and demons in general whom she thinks can protect her. In late 2007, she begins watching and spying on the Winchesters, waiting for another opportunity to strike. She make her move when she watches as John Winchester leaves the motel he was staying at. She watches him to make sure he wasn't going to come back anytime soon before going and knocking on the door, using her host body to gain Adam's trust before possessing him. She had been given orders by her boss to find and possess a Winchester in order to gain valuable intel on them in order to destroy them. She was smart and made sure to spy on them enough so that when she made her move she would be able to mimic Adam's personality enough so that they wouldn't suspect anything until it was too late.

Even though she was an upper-level demon that had possessed and killed many people over the years, Meg was still able to be beaten temporarily by Adam when he was able to use enough mental energy to get back into his body. However, Meg always won and she won back possession of him. Hower, she was soon found out when she went on a demon-killing mission with the Winchesters and the demon recognized her. The Winchesters soon started piecing together the events of the last few weeks and recognized that it was possible but not certain that Adam was possessed. They began spiking his drink with holy water and though she tried to avoid any drink that she hadn't made herself, eventually she made a mistake when she drank from a seemingly okay bottle of root beer and immediately began reacting to the toxic water.