Spoilers ahead for The Chilling Adventures of Sabrina Season 1. As Netflix viewers quickly discover, Sabrina Spellman is far from the only magical being in Greendale — and not just because she's surrounded by witches and warlocks. Her mortal friend, Rosalind Walker, has powers on Chilling Adventures Of Sabrina too. Her Nana Ruth calls this ability "the cunning," a psychic premonition passed down through generations of Walker women.
Unfortunately, this gift comes at the price of Ros' eyesight. As she reveals in Episode 3, Ros is suffering from myopic atrophy, or degenerative myopia. Her diagnosis means that she will lose her vision entirely within three months. Ros fears she's going blind due to a lack of faith (an idea that her reverend father and the demon version of Susie's uncle Jesse fuel), but initially, it seems like Ros' blindness is caused by Ms. Wardwell. Well, not the real Ms. Wardwell, but the evil Madam Satan who has possessed her. However, it all started long before Madam Satan came to Greendale.
As Nana Ruth explains in Episode 7, Ros' powers are part of her family history. "Generations ago, our kin accused a woman of being a witch. The other witches in Greendale, they cursed us Walker women with blindness," she explains. "I don't know if being cursed gave us the cunning or it simply brought out what was already there. But I do know, you will lose your vision. But with the cunning, you'll be able to see things that others cannot. And that will save your life."
Up until this point, Ros has remained completely unaware of the fact that her best friend is a witch and that the entire town is filled with magic. But as Ros' powers come into effect, her eyes (ironically) begin to open to what's long surrounded her.
During the funeral for Harvey's brother Tommy in Episode 8, Ros has her first premonition. When she picks up Tommy's hard hat, her mind transports her to the mines, where she sees Agatha and Dorcas using poppets. Ros doesn't understand this vision, but Sabrina is able to figure out that it means that two-thirds of the Weird Sisters were responsible for the incident at the mine that nearly killed Harvey and left Tommy dead. Eventually, Ros' cunning also makes her realize that Sabrina is a witch.
Since Chilling Adventures has already been green-lit for a Season 2, we can assume Ros' powers will only grow from here. What remains to be seen, however, is if she'll also lose her eyesight in the process. The Spellmans weren't directly responsible for the Walkers' curse, but perhaps Sabrina can figure out a way to save Ros' sight. On the other hand, the cunning could put her at odds with Sabrina, considering it's because of witches that she has to face these circumstances in the first place.
Whatever the case may be, her powers have already gotten her out of several sticky situations, and they'll certainly get her far when Chilling Adventures Of Sabrina returns — especially with all of that evil lurking nearby.