Claire Novak is the daughter of Jimmy Novak, Castiel's vessel. Jimmy offers himself over to Castiel, after his wife Amelia threatens to take Claire to her mother's if he does not get help. After Jimmy says "yes" to Castiel, Claire comes outside and says "Daddy?" Castiel replies "I am not your father" to her.
After almost a year of Amelia looking for Jimmy and thinking he was dead, he returns home. Amelia lets Jimmy talk to Claire and have dinner with them.
During their meal, their neighbor, Rodger stops over. He reveals himself as a demon to Jimmy, but Claire's mother, Amelia does not believe Jimmy. Jimmy puts Claire and Amelia in the pantry to keep them safe, but Amelia holds Jimmy back, so Claire can escape. Claire does, and when Jimmy and Amelia come out they see that Rodger is holding a knife to her throat. He makes the remark "I told you I'd gut the bitch." Claire calls out for her father as another demon attacks him.
Dean comes up behind Rodger and kills the demon with Ruby's Knife. This frees Claire and allows her to escape with her father. Claire, Jimmy, Amelia, Sam and Dean meet up outside the house and drive away in the impala.
Once they stop, Jimmy tells Amelia to take Claire to "Carl and Sally's" house. Amelia agrees and Dean, Sam and Jimmy drive off. When they do, Claire asks "Why is he leaving again?" Amelia slaps her and flashes black, demon eyes. She says "Cause it's just not my day, is it? You little bitch."
Jimmy, as instructed, comes to the warehouse where the demon possessing Amelia has Claire tied to a chair. Two demons bring Sam and Dean did. Amelia then shoots Jimmy and instructs one of the demons to "waste little, orphan Annie".
However, as the demon swings a pole at her, Claire suddenly wakes up, grabs it and smites the demon before burning free of her ropes. A horrified Jimmy realizes that Castiel has returned and has gained Claire's permission to use her as a vessel. Using Claire, Castiel is able to smite a second demon fighting Dean and watches as Sam drinks demon blood and exorcises Amelia.
Castiel tells Jimmy that he intends to use Claire as his vessel, and that Jimmy's work is done. But Jimmy convinces him to use him instead to protect Claire. Castiel leaves Claire and once again, uses Jimmy as a vessel, leaving Claire with her mother and no father again.
In The Things We Left Behind, Claire is shown as a problematic and erratic kid who keeps running from Group Homes. In one of these times she encounters Castiel, who poses as her father. After he helps her escape, Claire ditches Castiel to meet up with her surrogate father, Randy. However, Randy was in debt to a loan shark and when the loan shark came to collect, Randy willfully gave up Claire to the loan shark, who attempted to force himself on her. Castiel then arrived and rescued her. Unfortunately the loan shark's gang regroups and trap Dean, in which the others are forced to escape. When they come back into Randy's house, they find Dean covered in blood, standing over the thugs' bodies, including Randy, to Claire's horror.
In The Hunter Games, Claire is found by Castiel, who still tries to connect with her but she refuses, blaming Dean for Randy's death, as well as refusing to acknowledge that he betrayed her to save himself. She later meets a couple whom she confides her troubles to. When Dean calls her at Castiel's suggestion, the couple convince her to lure Dean into a trap so she could have revenge for Randy's death. At the end Claire changed her mind about Dean getting killed and warns him, in which he overpowers the couple, though rather than give into the Mark of Cain, lets them go. Claire then started going her own way, during which Castiel arrives in his car, having heard her informal prayer. Claire tells him that she has to make a new life for herself alone but promises to keep in touch.
During Angel Heart, in the months after leaving her group home, Claire begins a search for her missing mother. Having received postcards from Amelia and her things, including her diary after her final disappearance, Claire is able to track her mother to Tulsa, Oklahoma where she was to meet a man named Ronnie Cartwright. Ronnie claims not to know Amelia, but draws Claire's suspicion when he refers to her as Amelia Novak despite Claire not telling him her last name. Ronnie accidentally knocks Claire out and calls an ambulance which takes her to the hospital. As Castiel is in her emergency contacts on her cell phone, the hospital calls him and he calls in Sam and Dean to help him deal with Claire.
When Sam, Dean and Castiel arrive, Claire is not happy to see them, but tells them of her search before fleeing the hospital when they leave the room. However, she made the mistake of telling them where she was staying as well as checking in under her own name and finds Sam waiting for her while Dean and Castiel interrogate Ronnie. While Claire initially rebuffs Sam's efforts to help her, she finally agrees after he offers to teach her how to hack her mother's credit card records to look for clues. Claire is intrigued by how easy it is and insists on going with Dean and Castiel to investigate Ronnie's murder. When they return to the motel, Sam is able to figure out that the man Amelia was supposed to meet, Peter Holloway, has a farm that Amelia had been spending time around. Sam and Castiel go to investigate, but leave Claire and Dean behind for her own safety and because the Mark of Cain is starting to affect Dean worse.
Things between Dean and Claire are awkward at first, so Dean takes Claire to play mini-golf which they bond over. When Claire puts her putter in the last hole to demonstrate how the ball gets taken there, Dean realizes that the angel who has her mother used an angel sword instead of an angel blade and he and Claire research angels. Claire finds information on the Grigori, a class of angels that preys on humanity and when they are unable to reach Sam or Castiel, expects Dean to leave her behind while he goes to rescue them. However, Dean instead gives her a gun and instructions on how to use it and takes her with him.
Arriving at the farm, Dean and Claire investigate the barn and Claire is finally, tearfully, reunited with her mother. As Claire tries to help her weak mother out of the barn, Tamiel, the angel that had been feeding off of her arrives and tells Claire that Amelia is beyond saving. Claire tries to kill Tamiel with her gun, but he proves immune and tries to kill her with his sword. Amelia sacrifices herself to save Claire, leaving her devastated. Sam, Dean and Castiel engage Tamiel who proves stronger than all of them so Claire kills him with his own sword before embracing her mother's body.
The next day, Sam and Dean decide to send Claire to Jody Mills until she can get on her feet. Claire finally forgives Castiel for his role in her father's death, hugging him goodbye and asking Dean to look after him. She also keeps a stuffed animal Castiel got her for her 18th birthday. Before saying goodbye, Dean gives her a copy of Caddyshack and a lore book, having noticed her keeping Tamiel's sword. He advises her against becoming a hunter, telling her how dangerous it is and that she got her revenge when she killed Tamiel. Claire jokingly tells him he's pretty old when he tells her about how hunters don't live long and leaves in a taxi.
- Season 4
- Supernatural: War of the Sons (mentioned only)
- Season 10