Jenna is Toby's younger stepsister. She lost her vision after Alison played a "prank" on Toby and through a firecracker into the shed that she was in. She has been forcing Toby to have sexual relations since before she lost her vision, and threatening him if he refused.
Emily: You're lucky I don't take that stick...
Jenna: Careful, Emily!
I am still a target!Jenna