Rachel is one hot angel, and is played by Sonya Salomaa in the TV show Supernatural. Rachel is Castiel's sister, and is one of the many angels of the Host of Heaven. Rachel is supporting Castiel to fight Raphael and wants the Apocalypse stopped and Lucifer and Michael imprisoned.
When Castiel appeared in Heaven after the Apocalypse, after Lucifer and Michael were imprisoned, Rachel was the first angel to approach him and express delight he was alive. Rachel asked Castiel who to follow now, but Castiel wanted her to see she didn't have to follow anyone, but she refused, not understanding Free Will and wanting a leader.
Rachel first comes to Earth when Dean summons Castiel even though he knows Castiel is in the middle of a civil war, and Rachel appears rather than Castiel. This shocks the Winchesters, who ask her who she is, and she says she's a messenger of Castiel's. Rachel says Castiel is too busy at the moment to talk, and she points out how angel problems outweigh "petty" human problem. When Rachel hugely insults the Winchesters by calling them "petty hairless apes" Castiel himself shows up and greets the Winchesters, then tells Rachel to leave and he will be back.
Castiel tells the brothers that Rachel is a friend of his and is very business-like and can be stern. Castiel then helps the brothers with their supernatural situation, and then he returns to Heaven. However, Rachel is avoiding him. Castiel is confused, and he summons her to an abandoned warehouse where the two talk. Rachel says she heard disturbing rumours about Castiel's ambition, and that although she knows Raphael is dangerous, even more dangerous is Castiel's plans.
Rachel says about Castiel's "dirty secret" and she tries to stop him from carrying it out. She takes up arms against her brother, and she fights and wounds Castiel, but Castiel stabs her in the neck which kills her.