Osborne's Daughter was the Love Interest of Valente and she was played by Natalie Edwards.
She and her father were in charge of the manhunt for the Leviathans posing as Sam and Dean, but her father caught the real Winchesters instead, thinking them to be the killers. After learning the truth from Dean and seeing two Leviathans eat his men, Osborne helped Sam and Dean kill their doubles. Then, Dean got Sam out of jail. However, Sam had been traumatized by the Leviathan Dean telling him Dean had killed Amy Pond, a kitsune, and he eventually split up with Dean.
Osborne's daughter first appeared when the Leviathans had been decapitated. Her father said he'd got the drop on them and killed them both. Agent Valente was there and he congratulated Osborne and he appeared to flirt with his daughter and she apparently had a thing for him as she smiled at him and got more confident when giving him her report.
Later, Osborne and his daughter decided to lie about the bodies being burned because Dean had told them to keep the heads and bodies separate or the Leviathan would reform. So Osborne said the Winchesters were cremated. This angered the FBI but Valente kept order and said no bodies meant no paperwork, which was good. He smiled at Osborne's daughter and left with his colleague.
Osborne's daughter was later clearing up and asked her father what the lie was about. And she had also found black liquid which looked like blood but wasn't, beside the Leviathan, but she didn't know it was a monster's blood. She said it wasn't blood, and suddenly Valente appeared behind them, scaring Osborne's daughter, and he said "You're right, sweetie, it's much more than blood." This proves their feelings for each other. Osborne's daughter tried to smile but couldn't and suddenly saw Valente turn into a Leviathan, and kill her father and herself. She paid the full price for being a lying bish.