Lydia is Jackson's ex-girlfriend and is still trying to get over him. She also may possess a supernatural secret.
Stiles, you don't need instructions. You're too smart. When have you ever needed instructions? Stiles, you're the one who always figures it out, so you can do it. Figure. It. Out.Lydia
Lydia: Are you real?
Peter: Interestingly, that question can also be answered not yet.