- "I was 13. I thought it was a dream. I just lost control."
- ―Rahne Sinclair
Wolfsbane (born Rahne Sinclair) is a mutant with the ability to, partially or completely, transform into a werewolf.
When Dani comes to Milbury Hospital, she is introduced to four other young teenagers; Sam, who can propel through the air, Illyana Rasputin, who can conjure magic and travel between another dimension called Limbo, Roberto da Costa, who can transform into a humanoid sun and lastly, Rahne Sinclair who has lycanthropy. Rahne is revealed to have escaped her religiously strict village who branded her.
Dani is antagonized by Illyana who insults and belittles her. After a failed attempt at escaping, Dani tries to jump from the church tower, but is stopped by Rahne who takes a romantic interest in her. Later, Rahne tries to use the confessional booth and begins hearing the voices of the villagers who chased her out.
Eventually, the group come together when Illyana spikes Reyes' coffee with sleeping pills and they run amok on the grounds. They collectively believe that they are being trained to become X-Men, hence the strict supervision, as well as Reyes reminding them that they are considered dangerous and should not leave until they are under control. Dani and Rahne enter a romantic relationship with one another. Later, Rahne has another vision of Father Craig Sinclair appearing in the bathroom and branding her on her neck. The group finds Rahne severely injured and Illyana confronts Dani, knowing what her power is now. Reyes prevents the two from fighting.
Reyes consults her employers who turn out to be Essex Corporation and they instruct her to kill Dani. As Reyes takes Dani away, Rahne immediately suspects that something is wrong. Dani uses her powers to learn of Reyes' true intent, but Rahne arrives in time and severely injures Reyes, forcing her to flee. The New Mutants regroup and realize that in order to escape, they have to kill Reyes. They find her and she reveals that she was training them to be killers for Essex, but that Dani must die due to her dangerous Mutant abilities. While fighting the Demon Bear, Rahne attempts to speak to an unconscious Dani until she eventually goes to fight as well.
As the sun rises, the New Mutants collect their belongings. Sam notices that the barrier is no longer around them and they all decide to head into town since Reyes had previously told them that the nearest town was twenty miles out. Not knowing if she was telling the truth, they all decide to head out together as a family; as well as Dani and Rahne continuing their romantic relationship, facing the unknown.
Especially around Dani, she is caring and will risk her life to protect her.
- Lycanthropy: Rahne is a mutant with the power to transform herself into a wolf. However, she is not a real werewolf, and, therefore, is not restricted to the limitations of a creature of the night. She can transform into either a wolf or a transitional, wolf-human stage at will, without any effect of the full moon or silver-based items. She can also retain full memory of herself, and therefore has her human consciousness while in her wolf and transitional forms. As a wolf, Rahne experiences all the heightened animal senses of a wolf, such as hearing, sight and smell. However, it is in her transitional hybrid form that she experiences greater changes. She is essentially a human being covered with a thin layer of fur all over her body, sharp teeth and claws. She is able to stand erect on her legs and retain the use of her hands, but is also able to run and maneuver on all fours like a wolf. In this transitional form, she experiences enhanced abilities such as:
- Enhanced Strength: In her half & full wolf form, Rahne possesses greater strength than that of a normal human.
- Enhanced Speed: In her full wolf form, Rahne possesses greater speed than a normal human.
- Enhanced Agility: Although enhanced her muscles and skeleton are also extremely flexible, giving her the agility of an animal.
- Hyper-Keen Senses: Keen animal senses of sight, smell & hearing combined with human intelligence are heightened further than that of a regular wolf. She can perceive infrared, ultra-violent, heat, heartbeat, health, pheromones, feelings & emotions such as anger, shame, grief, disgust, fear or lust.
- Claws & Fangs: In her half & full wolf form, Rahne possesses sharpened nails along with pronounced canines with which to rip and tear through most substances.
- Rahne's name appeared on the Department of Domestic Security and Defense computers in X2: X-Men United.
- Josh Boone confirmed that Rahne and Danielle Moonstar are in a romantic relationship in The New Mutants, making them the second set of LGBTQ+ characters to appear in the X-Men film franchise after Negasonic Teenage Warhead and Yukio.