Braeden is a mercenary fully aware of, and active in the supernatural. Braeden is a former US Marshal. Her employent was terminated after she obsessively searched for a single target: a supernatural assassin known as the Desert Wolf. Braeden then took up a job as a mercenary while using a US Marshal as a cover.
Braeden makes a living by taking on dangerous jobs. She is an deadly warrior, an expert in hand-to-hand combat, counter-intelligence, and firearms. Braeden will charge her clients for the deeds she takes, but she's shown to be altruistic, spontaneous, helping and defending innocents with good reason with no financial incentive, and is fearless.
Braeden was hired before the start of Season 3 by Marin Morrell to rescue Isaac Lahey when he was kidnapped by the Alpha Pack while attempting to find Erica Reyes and Vernon Boyd.
In 3x14 - More Bad Than Good, she saves Derek and Peter because Deucalion hired her to do so.
In Season 4, Braeden appears again under the employ of Araya Calaveras. She leads Scott to la iglesia so they can rescue Derek. The person they pull from the nagual temple turns out to be Young Derek.
Peter and Derek hire Braeden to find Kate so that Derek can find out what she did to him. She poses as a federal Marshal to get medical records on the wendigo who turned up at the hospital, but it doesn't contain anything useful. She disappears, and the next time Derek sees her, she's in the field of dead Werewolf with a bullet wound. He brings her to the hospital and waits at her bedside.
Braeden informs them that there was another assassin in the woods who shot her. She's surprised to find Derek waiting at her side, and he jokes that he has to protect his investment. She goes home with Derek, and he sleeps on the couch. She sneaks up on him and tries to investigate the wound he got by jumping in the way of the bullet meant for Satomi, but he quickly grabs her wrists. He doesn't want to show her his eyes, but eventually relents. Braeden dresses Derek's wound so it doesn't get infected and gives him some basic lessons on protecting himself as a human. She takes a pistol from his hand a few times, until he takes a cue and kisses her to get past her defenses.