AN: Hey guys! No, I cannot leave Allison's death alone. There is just so much potential for Lydia to really expand as a character and deal with her best friend's death, but I just think they'll focus on Scott and completely move on. And give her another guy.

No.

She needs time and closure.

So this is a crossover, kind of, with The Mortal Instruments fandom, in so much as that's where Institutes and parabatai come from. They're a really good book series, I'd recommend them! So a parabatai is someone who you share a bond with. You get matching runes that bind you together, and you are bond together until one dies, and then it fades. They're your best friend, brother/sister, training partner and other half rolled into one. You complement each other completely, and can feel each other's pain. I'm not explaining it very well, google it if you must!

I can't take credit for the idea, I saw it on a twitter account I follow ( shellLoveStiles ) and I don't think it was her idea, so I don't know who to credit it to unfortunately!

These are the two songs that I listened to on repeat as I wrote this, it's a tearfest all round. I recommend you do the same while reading! The songs are 'Say Something' by A Great Big World and Christina Aguilera and 'Forgetting' by David Gray.

Itching and scratching

Punching and hitting

Forgetting, Forgetting, Forgetting

Forgetting

Reminding rewinding

Removing regretting

Forgetting

-Forgetting, David Gray

You knew.

She felt it happening before it even did, her pounding heart giving it away as she dragged to drag Stiles along, desperately putting an izrate on his arm. "Come on," you pant. "We have to keep moving, Stiles, we have to get to th-"

You feel it then.

The burning pain as that blade is pushed up through your stomach. You gasp, and desperately swing your seraph blade at murderers that aren't there.

It's then that you realise that it wasn't you.

"Allison!" The scream tears itself out of your throat as you collapse in pain, from the loss you know you're about to face and the feeling of the blade in your heart.

It isn't you, but it might as well have been.

You don't remember much after that.

You remember crawling through the dirt of the tunnel floor to get to her.

You remember thinking that it can't have been her. Not Allison, she was the best Shadowhunter of your institute. Scott was the heart, Stiles the brain, and Allison the warrior. It couldn't be Allison.

But it is.

You learn that some of her last words were making sure you were safe.

It happens in fragments. People are around you, whispering.

Melissa is leaving food at your door, Mr Stilskini is checking on you every hour.

You speak to know one.

Instead you sit at your mirror, your hair over your neck, until you tell yourself to suck it up. You're Lydia Martin. You can do this. She deserves this. You pull your hair away from your neck and there it is, your parabatai rune. It's a shade or two lighter than original, and slightly distorted, but it's still there. You smile, because Allison still lives on. As long as you have your mark, she's still your parabatai. Still here. You can see her, a short skirt here, a smile there, the tinkling of her laugh haunts you. "You won't let me go, will you Lydia?"

It starts fading.

It starts fading and you crack.

You can't handle it.

You're screaming, crying until you throw up, and your room is trashed. Your books are torn to shreds-your precious knowledge is useless now. It didn't see her death and a way to prevent it. You can't stand the sight of yourself, knowing that you weren't there. You lash out and punch the mirror, your hands bloody. You're wild, and there are worried whispers and then shouts in the hallway, and Stiles is there, holding you as you struggle, and Scott is trying to hold your arm out so Melissa can heal your hand, but you've always been a scrapper in a fight, and they back off. Stiles remains, his arms around your waist and arms, keeping you secure so you can't do yourself any more damage. "Lydia, please. Lydia, stop. You have to stop, please. This isn't you-"

"I don't know who I am anymore!" you screech. "Who am I without her?"

Allison's gaze softens as she flops down on your bed among the madness. "I'm still here, Lyd's."

"Lydia, don't-"

"Get out, get out, get out!" you scream and struggle until you throw him, punching and hitting until he's out of the room. "Leave us alone!"

You're sitting together in her room with the door closed, like it used to be. You close your eyes. "They think I'm going crazy," you comment.

"Are you?" she teases, and you give her a look.

"Well, they think I'm talking to a-" you stop abruptly, frowning. You can see her flickering before your eyes, and your parabatai looks sad, so sad.

"I know," she whispers, and you lie down on her bed together, like you've always done since Allison and her family came to live at the Institute. Her hair falls away from her neck when she lies down, and you frown. "Where's your mark?" Allison almost looks at you guiltily.

"The dead don't have runes, Lydia. I can't-mine faded quicker than yours." You blink and instinctively reach for your neck. She smiles, and you know she's worried about you. She always is. Was. Is. It's such a blurred line now. "Just because the rune is gone and-and I am," she swallows, "doesn't mean we aren't parabatai. You're still my best friend." She can see the tears filling in your eyes and grabs your hands. "What was the first thing you said to me?" she asks.

"Where did you get your jacket?" you reply automatically, and she giggles.

"The first important thing, Lyd's."

"You're-you're my new best friend," you whisper brokenly. Allison gives you a half smile in response. "I'll always be your best friend, Lydia. You'll always be mine."

"Always," you repeat drowsily, and fall asleep.

Stiles finds you, curled up on her bed in one of her dresses, on one half of the bed with your hand out as if someone should be holding it.

His heart breaks when he knows that someone should be, and she's not there.

You're the training room again, practicing your throwing knives because Allison always was the better shot. Now you have to be, for both of them. Scott and Stiles are fighting it out on the other side of the room, the sort of easy bond and teasing that happens between parabatai that leaves you with a chest ache. Kira is there, and she's chatting away to you, like she always did with that nervous habit. "I just don't know how much time or space to give them. I know Scott is hurting, but I just want to be there for him. I know I can't replace Allison, I can't replace what he's lost-" the poor girl is cut off by one of your knives lodging itself solidly in the doorframe right beside her head. She flinches, and looks at you wide eyed. "They're hurting? What they've lost? Give them time?" you stalk towards her. "Listen, Kira. I like you. But you know nothing about loss," you hiss. "So I'm going to live up to my selfish, bratty name and freak out a little because she was my parabatai. My best friend. And she's-I lost her," you say roughly. "Scott may feel heart ache," she glanced towards where Scott and Stiles have now stopped fighting, and are instead watching the two girls, "but I don't have one anymore. It's been ripped from my chest and is now six feet underground." You haphazardly place the knives back in their stand. "I don't feel good, I'm going back to my room. Sorry if I'm not feeling chatty," and you storm out. Allison is there, looking at you with those disapproving eyes, but not judging, never judging. "You shouldn't have done that, Lydia," she sighed. "You scared poor Kira."

"I know," you reply wearily, scuffing your shoes on the hardwood floor. "You have to go soon, don't you?" you ask, dreading the answer you already know.

"Yeah," she chokes out. "Yeah I do. It's okay, mom will be there, she is waiting."

You frown. "Then why are you still here, Ally?"

She smiles ruefully at you, twisting your heart. "Isn't it obvious? I have to make sure you're okay."

"I'm keeping you here," you say, half horrified with yourself and half glad, because you really don't want her to go.

"No, not exactly! But…yeah," she admits, and twiddles her fingers, a nervous habit from over the years. "You're doing good, Lydia. You're doing better than you think. You'll be okay without me," she whispers, and suddenly your parabatai seems very small.

You haven't seen her in a while, and your room is still trashed, so you head to hers and slip inside, finding solace as you always have, before and after what happened. "Oh," you say, stopped in your tracks when you see Mr Argent sitting on the edge of his daughter's bed, looking around at his daughter's things. He glances up at you, surprised, and you say "I can go, if you want." He stares at you for a moment before shaking his head. "No," he says gruffly, and you can tell he's been crying probably as much as you have. "You should stay. It almost feels like between the two of us we can keep her here with us." You give him a small smile at that, and perch on the edge of the bed beside him. "How-how are you doing, Lydia?" and you can tell this is hurting him as much as it's hurting you because you look at Mr Argent and all you see is Allison, and you know he looks at you and thinks the same. "Not great," you admit, "but I'm….I'm here." Truly, it seems like the best answer you could give the poor man. "The same here. Some days are worse than others, but…I'm coping."

"How's the rune?" he asks bluntly, and you appreciate that. He's the only other person here who knows what you're going through and isn't acting like you're crazy.

"Fading," you reply tightly.

"Does it hurt?" he asks curiously, and you know it's because he doesn't have a parabatai.

"Every damn day. It's like losing her every day, and I wake up and do it all again. I feel like a ghost, I-I felt the blade, and I shouldn't-I shouldn't be here, I shouldn't be here, not in a world where she isn't." You're crying now, and Mr Argent is pulling you to his arms like you've seen him do with Allison many times, especially after her mom died. "I know," he whispers, "but we'll get through it. We'll get through it because we have to. Because she'd want us to. We'll get through this, kiddo."

The rune is faded to a faint grey scar now, and you know it's over. You look in the mirror, but you do not cry. It still gives you a catch in your throat and a hitch to your breath, but you aren't breaking down and feeling like the wind has been knocked out of you like you once did either. You turn stand up and look at her, where she suddenly appeared. "It's time now, isn't it?" you ask and she nods. You grimace and nod back. "Okay."

"Okay?" she quirks a brow.

"Well, not okay," you amend. "But maybe-someday. I can…I'll be strong now," you're determined, and she squeezes your hand. "You always were. I love you so much, but I'm okay now. Really. I don't feel any pain. Just…be happy again, okay Lydia?"

"I'll try," you promise, choking back tears. You're about to say the words that you know make it final, that mean it's really true. "You're my sister and my parabatai. I love you, so much, and I wouldn't trade our friendship for anything." You look her in the eye, and you can see it-the hope she has for you and herself, the hope for happiness and better things. You take a deep breath and say the final words. "Goodbye, Allison." She grins, laughing, and fades into light, and you find you don't want to cry. You're happy for Ally, you know she's found peace. You just have one more thing to say, then it is complete. "Ave atque vale, Allison Argent."