The 18-year-old daughter of Harry Mason. They have been on the run for the last six years from forces she doesn't understand, and haunted by nightmares. After her first day at her new high school, her father is missing and a mysterious message is left in their home: "Come to Silent Hill". She then goes to Silent Hill with Vincent Cooper to find her father. She is really Sharon Da Silva, who was the living manifestation of Alessa Gillespie's remaining innocence.
Action Girl: Carries a gun with her during Silent Hill and willingly takes on several monsters and the Leonard monster to retrieve the Seal of Metatron.
Apocalypse Maiden: The Order of Valtiel intend to use Heather's body as an incubator for their unborn god. Turns out Claudia's side of the Order wanted Christabella's side to do this by burning Alessa alive. It did not work out so well.
Helpless Good Side: Averted. She doesn't have Alessa's psychic powers or knowledge of Silent Hill, but she's no longer a helpless child and her fusion with Dark Alessa suggests that she's become the stronger half.
Plucky Girl: Willing to go face the horrors of Silent Hill in order to rescue her father.
Sleeves Are for Wimps: Averted. Heather wears her trademark armless jacket, but wears an orange, long-sleeved jumper under it.
Tall, Dark and Handsome: He jokingly references it by name when trying to talk to Heather, but she points out that he isn't that tall.
Troubled, but Cute: Vincent is a teenage Mr. Fanservice who wears a leather jacket, talks back to the teacher, and is hinted to have a difficult family. Though this trope only really comes into play when it's revealed he's Claudia's son and originally befriended Heather to get her back to Silent Hill but became conflicted about his mission.
White Sheep: Despite being Claudia's son and Leonard's grandson, he has a crisis of conscience upon realizing Heather is innocent and not evil incarnate as he was told, and confesses to her rather than continue to lead her into their trap. Compare the rest of his family's almost gleeful willingness to sacrifice her anyway.
Played by Martin Donovan
A middle-aged detective hired by Claudia Wolf to track Heather down. He gets dragged with her into the Otherworld.
Cloud Cuckoolander: Condemned to the asylum by Claudia when she accused him of being corrupted by Alessa's darkness. Turns out he just knows she had been corrupted herself, knew she was the Missionary, and knew the true purpose of the Seal of Metatron.
Voluntary Shapeshifter: Leonard completes the Seal of Metatron and transforms into a monster to deliver Heather to the Cult. Heather manages to pull out the Seal and kills Leonard.
Claudia Wolf / The Missionary
Played by Carrie-Anne Moss
A priestess of the Order of Valtiel, who needs Heather to return to Silent Hill, so she kidnaps her father as leverage. Claudia is actually the sister of Christabella and Dahlia, intending to use Heather to incubate the god of the Order and purge the world of sin and evil. She is also the Missionary who appears throughout the film.
Abusive Parents: Raised Vincent to find Heather and bring her back to the town.
Expy: Her missionary form is based heavily on three different monster designs from the Hellraiser franchise. Her black leather clothes and the way her skin has been peeled back to expose the flesh underneath is heavily reminiscent of the Angelique Cenobite from Hellraiser: Bloodline. Furthermore, the way the blades are lodged into her skull is an idea taken directly from Hellraiser III: Hell On Earth's CD-throwing Cenobite. And finally, the way her lipless mouth exposes all of her teeth is identical to the mouths of Hellraiser's Chatterer and Torso Cenobites.
Freudian Excuse: Willing to hurt those who get in her way as long as she can complete her goal.
Voluntary Shapeshifter: Really the Missionary, and the Seal of Metatron under Alessa's influence reveals this to her followers.
Well-Intentioned Extremist: Wishes to use Heather to incubate and eventually give birth to the God of the Cult to purge the world of evil. The Cult intended to do this with Alessa years ago, but it went wrong thanks to Christabella.
Rose Da Silva
Played by Radha Mitchell
Sharon's adoptive mother, she is still alive after being trapped in the foggy world of Silent Hill with Alessa.
Dahlia's daughter, a powerful girl with amazing psychic powers. Burned by the Order, Alessa's rage awakened the true potential of her powers and she dragged Silent Hill into a hellish nightmare to punish those who wronged her. Heather is the reincarnation of her innocence, who she sent off to safety and turned her darkness into Dark Alessa. However, upon Heather's return, Dark Alessa materializes as the Memory of Alessa to absorb her good self, only for Heather to instead absorb her and they become one.