ABILITIES: Lydia is a banshee. The description in that link, while technically complete, is also a little scattered, so here are the basics.

• It is unclear so far whether Lydia's abilities are genetic (unlikely, unless her mother and father are significantly less ordinary than so far portrayed) or just vaguely magical; however, if (if) Peter Hale is to be believed, they required a traumatic event to kickstart. He alleges that his attack on Lydia was that catalyst, but noticeably doesn't say whether a near-death experience is the only possible catalyst. It's possible he just enjoys traumatizing teenage girls! It is worth noting, however, that after the bite, Lydia experienced violent hallucinations, blackouts, and dissociation/sleepwalking, some of which can be attributed to standard trauma but much of which was probably the birth of her banshee abilities.
  
• Theoretically Lydia is a harbinger of death, but . . . also not quite. She is able to predict (in dreams and by vague "bad feeling"-type instinct) the locations and natures of deaths; in this way she finds a lifeguard who's been killed, although she doesn't realize the destination she's driving to or why she's driving there. So it might be more accurate to say she senses death, both before, after, and during it happens.
  
• Lydia possesses a piercing scream! This is in and of itself not an incredibly remarkable ability. While it's probable that with some practice it could be useful as a weapon, at this point in time it's mostly just an incredibly loud noise that can be heard miles away. Its other function - again according to Peter Hale, but generally borne out by actual events on the show - is as a means to drown out all other sounds so that she can focus on . . .
  
• . . . the voices in her head! Or, not quite in her head. Lydia can hear whispers about death and dying, which appear to be what she has followed instinctively to find dead people for all of the third season. These voices apparently belong to other banshees in some kind of network of the dead, which is possibly the most cheerful sentence I've ever typed.
  
• All of this means that it's entirely up to modly discretion whether Lydia has access to any of her power, limited power, or full power with the explanation that the banshee network is interdimensional or some such. I am totally fine with whatever is deemed most suitable for the setting.
  

INVENTORY; The clothes on her back and the contents of her purse: a taser, gum, twenty-ish bucks in cash and change, credit cards, a copy of Death by Black Hole, and bobby pins.
ANYTHING ELSE WE SHOULD KNOW? At this canon point, Lydia has claw wounds on the back of her neck and base of her skull from when Scott stuck his little wolf claws into her to drag her into Stiles's mind. THEY WILL BE FINE, they're not were-infected as far as anybody knows, but they are currently there.

FIRST PERSON:

That one was interesting.

[She means it, too. She's as genuine as she ever gets, bright and fierce and most of all intent.]

A lot of the logic was faulty, but the overall concept was sound. The line between dystopia and utopia seems a lot thinner lately, living it over and over. But at least I got to fly a spaceship.

It made me wonder about relativistic travel, though. It seems unsustainable, like a society couldn't survive like that no matter how long-lived its inhabitants. After all, society's built on social ties, isn't it? But if you travel once and come home to everyone you've ever known dead - that's no way to live.

[Which is almost all. But then, with more typical sarcasm:]

The Trumps have thought about sustainability, though. So there's nothing to worry about at all.

THIRD PERSON:

Lydia doesn't expect to approve of the telepathic network. She certainly doesn't expect to like it - she gets tired enough of the slow pace of other people's actions that the idea of exposure to their thoughts is exhausting.

But it's not that simple, of course. Nothing worth it is ever simple.

She sits in the middle of a vast expanse of white-tiled space, fading to grayscale in the distance. In front of her is a steaming cup of pekoe, bathing her face in impossible, humid warmth. On either side of her, oppressively audible, is silence; she cocks her head to listen for anything, but no luck. Or all the luck: everything's a matter of perspective.

Liminal space strikes her as a malleable quantity. Not entirely, but it's not stiff, just as the mind itself isn't.

Her eyes drift shut against the blinding whiteness and the seeping gray. She holds her hands over the steam.

When they move, her fingers mold the steam into transient shapes that evaporate almost instantly - but in her mind's eye they stay. The long walk of the entrance hall at Beacon Hills High; the street in front of her house; a few seats in a row at the movie theater. Then things smaller and greater: her entire house, down to the trellis in the backyard; her favorite pair of shoes; Jackson, although he blows away in the blink of an eye, and there's not a thing she can do about that.

She doesn't regret it, when she exhales and blinks and looks out at the unworld again. There is the spark of discovery in her eye, even though her tea is cold. This place might not be real, but the nature of reality is, as she knows so well, relative. There are answers to be found, and she will find them, even if she has to experiment.

It's not as though this is the first time she's had to take her own initiative.