Naomi
Naomi, portrayed by Amanda Tapping, is a mysterious angel who commands a garrison in an area of Heaven previously unknown to Castiel. She was responsible for rescuing Castiel from Purgatory; although it took several angels to do so, and many of them died in the effort. He was subsequently returned to the Winchesters. She has since revealed that she has the ability to call him to her to 'check in' about the Winchesters' current progress in the search for the Word of God tablet and erase his memory of these check-ins after the fact. When Castiel chooses to return to Heaven to make up for his previous actions, Naomi forbids him from doing so, though she seems sympathetic to his desire to make up for his mistakes. Naomi tells Castiel that by following orders he is making up for what he has done and asks him what he wants to do when he is unsure of what to do next. This causes him to consider his options fully for the first time. Naomi later sends Castiel to rescue Samandriel after getting a distress call from him, but after learning that he has revealed the existence of the angel Word of God tablet, she orders Castiel to kill Samandriel which he has no choice but to do. Naomi calls Castiel a hero for it and reveals that the existence of that tablet is something that any angel, including herself would die to protect as it could cause great harm if it falls into demon hands. She then has Castiel bring Samandriel's vessel back to Heaven so she can determine just how much he broke, but draws the Winchesters' suspicions that Castiel is being controlled in the process. Castiel also remembers her having him tied down to a chair and approaching his eye with a mysterious instrument while he screams. In "Goodbye Stranger," Naomi has apparently indoctrinated Castiel completely to her control as he is now completely ruthless and has killed thousands of Dean copies for her to prove it. Naomi sends him to get the angel tablet before Crowley can and has him lie to the Winchesters about what he is doing and kill a demon before she can tell them the truth. Though she allows Meg to remain alive, Naomi orders Castiel to kill Dean once he retrieves the tablet. However, Castiel manages to fight her control and pick up the angel tablet which breaks her connection with Castiel and her control over him. After Castiel disappears with the tablet, Naomi meets with Crowley who its indicated she has had a sexual relationship with and she tells him that Castiel is doing what he is meant to do: protect the tablet, even if it means protecting it from her. She refuses the offer of a deal from Crowley and is later shown getting a report on how the angels have failed to locate Castiel and the tablet. In "Taxi Driver," Naomi appears to Dean at Garth's houseboat and tries to convince him that she is on his side. Naomi claims that she was just meeting with Castiel periodically and that he misinterpreted her orders and tried to kill Dean as a result of mental instability. Dean doesn't trust her, but she tells him that Sam was traveling to Hell through Purgatory before leaving. Later, when Crowley prevents Sam from releasing Bobby's soul into Heaven, Naomi intervenes to stop him. He tries to convince her not to, claiming they will seal up both Hell and Heaven, but Naomi tells him that she hopes he gets locked up and she will figure out the rest before trying to smite him when he calls her a bureaucrat. Crowley flees and Naomi frees Bobby from Crowley's trap, letting him go to Heaven and tells Sam and Dean she wants the same thing they do: Hell sealed. In "The Great Escapist," Naomi and her angels manage to capture Castiel and interrogate him about the location of the angel tablet. Naomi reveals that Castiel has taken part in many atrocities, but she has wiped the memory of them from him. Before Naomi can do much, Crowley shows up with a gun that can kill angels and she is forced to flee when he fires at her. Metatron reveals that she is just one of many faction leaders in "Clip Show," not the ruler of Heaven as previously believed. In "Sacrifice," Naomi captures Metatron and tortures him to learn what he is up to. Horrified by what it is, Naomi rushes to Earth to warn Dean and Castiel: Metatron is not trying to close the gates of Heaven, he is trying to permanently expel all angels in revenge for his own expulsion. Naomi expresses remorse for her actions and that of the other angels, saying that angels are meant to protect humanity and they have lost sight of that somewhere along the way. She warns Dean that if Sam completes the trials, he will die and offers to hear Castiel out if he truly wishes to return to Heaven. Naomi leaves and when Kevin can't confirm her story with the angel tablet, Castiel refuses to believe her, though Dean does. Castiel travels to Naomi's office in Heaven only to find that Metatron has killed her by impaling her in the head with her own torture spike. Metatron confirms that Naomi was telling the truth.
Read more about this topic: Characters Of Supernatural, Angels