I had to listen to the audio many times. :( OC is on the left. Her name is Kai Rosa. She's an angel-witch hybrid and every angel-witch hybrid gets assigned a person to protect. After she aided in Sam and Dean's fight against the yellow-eyed demon, she dies. Hence, this is her and Sam's conversation before she died. (To clear up confusion, the cut on Sam's cheek is from the yellow-eyed demon, and Kai was assigned to protect Sam.)
