Jace was begging them—begging them—to kill him, to end it all, free him from Lilith and all the harm she was causing him, causing him to cause to other people, to strangers and loved ones alike. And Izzy wouldn't do it, and maybe that made her better than Alec, maybe it made her stronger, more sure of the fact that they would find some other way. Maybe she was just a better person than Alec; she showed zero hesitance, seemed disgusted and distraught over the fact that he was even asking…
And maybe that was why Jace picked up the knife from the ground where Izzy had thrown it, and went over to Alec with it instead; he knew Alec as well as Alec knew him, and he could see in Alec's eyes that he was weak, that if he came to Alec to ask him what he had just asked Izzy…
Alec didn't know if he could say no.
He looked into his parabatai's eyes as he held the knife to his chest, fingers on the end of it, on Alec's hand, strong and determined but shaking. He was afraid. He was so afraid but he was sure, and Alec didn't know what to do. He knew, as his brother—as his family—the right thing to do was to say no, was to drop the knife, pull him in for a hug and tell him that they were going to figure it out.
But as a Shadowhunter, the Head of The Institute… it was his job to do as Jace asked.
It was safer for everyone if Jace was out of the equation; if they didn't have to worry about hurting him, they could come up with a way to get rid of Lilith. As it was, they couldn't do anything, as focused as they were on saving Jace. From a practical standpoint, killing Jace made the most sense for the safety of the world. More than that, it would restore the balance of the universe: Jace had already been brought back from the dead, and some part of Alec knew that things like this were going to continue to happen until he was there once again, and stayed there. He was supposed to stop things like that, if he could. And he could.
It was Alec's job to kill Jace.
More than that, as his parabatai, as someone who was connected to Jace's heart and soul and very being, as someone who could feel what he was feeling, who knew him better than he would ever know anyone else… it was his job to relieve Jace of all the pain he was in. He was being tortured in the worst possible way, in ways Alec could only understand a fraction of—for everything that Alec felt from Jace, he knew Jace was going through ten times more, and that fact alone made his heart hurt more than losing Jace would.
As his parabatai, it was his job to put an end to Jace's suffering.
"Please, Alec," Jace whispered, and Alec started sobbing at the words, because he knew, as well as Jace did then, as well as Izzy did, that he was going to do it, that he had no choice.
"Alec, you can't—"
"Izzy," Alec said, eyes still on Jace, refusing to leave his parabatai. "I have to. God, I have to. He's my parabatai. I can't let him… we don't know how to stop her, Iz, he could… he might suffer like this forever, and I am supposed to protect him. We made a vow, and if I could lay down my own life for him right now, if me dying would save him… I would do it in a heartbeat. But I can't, Izzy, I fucking can't. And if he thinks dying... If I have to kill him to save him from this… I have to do it. I have to do it. I owe it to him," he insisted, already feeling his own heart break as the reality of what he was going to do sunk in.
And God, it already hurt so much, just thinking about it. He had felt Jace die once before, had felt that pain, had felt part of his own soul leaving him as he felt Jace's leaving himself; his parabatai rune had vanished and he hadn't known who he was or what he was going to do. His life had lost meaning for those few moments that Jace had been dead, so what would it mean to lose Jace for good? More than that, what would it mean to be the one to kill him? To be the reason he felt Jace's soul leave his own body and part of Alec's? What would it mean to kill his parabatai and feel that pain all over again? To never again see that rune on his hip? To feel lost and alone and disconnected for the rest of his life?
His life was going to change, and he was never going to be the same ever again. And he had to be okay with it, had to find a way to make peace with it. Not now, but eventually.
"I love you, Izzy," Jace said, seeing the determination in Alec's tear filled eyes as well as Alec knew he would.
"I love you, too," she said, already sobbing under the weight of what was about to happen, and Alec felt bad that she was going to have to see this; he would rather she didn't, would rather she not think of Jace in the way she was going to see him when he was… when he was gone. He was glad, in some small part of himself, however, that it was him doing this and not her. She shouldn't have had to live with the pain and guilt that Alec was going to have to carry for the rest of his life, she deserved better.
"I love you, Alec," Jace said, eyes never leaving Alec's for a moment. He knew, Alec knew, that his parabatai needed him and his strength now more than he ever had before in his life.
"I know. I love you, too. I… it's been an honor, Jace, to have you as my brother, as my parabatai. No one else could have…" Alec faltered, choking on a sob. God, there was so much to say, and not enough time to say it. Never enough time to say it. How could he decide what was worth saying, and what could be left unsaid to haunt him for the rest of his life?
"Entreat me not to leave thee—" Jace started, interrupting his thoughts, and Alec had to close his eyes for a moment, take in a breath before he could open them again and found Jace's scared, sad eyes.
"—or return from following after thee—" Alec began finally, voice shaking.
"—for whither thou goest, I will go—"
"—and where thou lodgest, I will lodge—"
"—thy people shall be my people, and thy God my God—"
"—where thou diest—"
"—will I die—"
"—and there will I be buried—"
"—the Angel do so to me, and more also—"
"—if aught but death part thee and me," Alec finished, and without another thought or word, and choking on his tears, Alec and Jace both pushed the knife through Jace's chest, and Alec brought Jace to his own chest, hugging him close as the blade pierced his heart, and he started choking on his own blood.
It was as easy and as hard as that.
Jace gripped Alec as tightly as he could as, and Alec held him back, feeling every ounce of pain that Jace was in just then, could feel his chest tightening, could feel himself choking on blood that was not in his own lungs, could feel the cold absence of life taking over him, felt a searing pain in his hip that would have had him on the ground curling up in pain were he not holding Jace in his arm. He owed Jace this, to feel every bit of pain and embrace it, the final moments of his connection with his parabatai.
He could barely hear Izzy's cries, everything around him drowned out by the pain he was in. It would pass, he knew, most of it would pass and he would be able to drop Jace and comfort his sister instead. But for now, she was just as much alone in this as Alec would be forever more, and he would feel guilty about that for the rest of his life as well.
"Until we meet again, brother," Alec murmured into Jace's ear, wondering if he was already gone by that point. It was all so overwhelming and all encompassing, Alec barely knew if he was still alive, let alone if Jace was.
Eventually, Jace's grip on Alec fell limp, and Alec felt his own heart stop beating for a moment, felt the air leave his lungs once again in a terrifyingly cold way, and he knew, God, he knew Jace was gone. He clung to his limp body for a moment longer until he could breathe again, until his lungs decided they would continue working after all, despite not being connected to Jace's any longer. And then he dropped Jace, reluctant, let his body fall to the ground in front of him, and he fell to his knees, sobbing hysterically and covered in his parabatai's blood.
Jace looked… at peace, he thought in the far corner of his mind. Not happy, but at peace. He looked like he wasn't in pain anymore, and Alec could take comfort in that for a moment, until he was no longer staring down at Jace's dead body anymore. Instead, he felt a kind of warmth surround him that he recognized as Magnus' magic, and he knew the warlock was pulling him and Izzy out of there, perhaps having sensed that something had gone wrong, or just not being able to hold the connection any longer. Either way, Alec was both grateful and not for it.
A moment later, Alec was kneeling on Magnus' floor, the blood gone from his hands, his chest, his skin, but still in his mind. In his mind, he was never going to be able to escape the blood he had spilled that day. In his mind, he was forever tainted, forever alone, forever in pain.
"Alexander?" Magnus' smooth, worried voice said, and Alec realized that he was still sobbing uncontrollably then, that he couldn't hear any of what Magnus was saying other than his name, couldn't hear Izzy explaining, in her own frenzied, sobs, what had happened. He was broken. God, he was so fucking broken and it was no one's fault but his own.
"Oh, angel," Magnus murmured, arms wrapping around Alec suddenly.
And Alec didn't think, just let himself be held by Magnus then, let himself cry into his shoulder with all the pain that he felt. He felt so useless, like he would never be able to fight or lead men ever again, like he would be less of a leader without Jace, without his strength. He felt like all he would ever be able to do was cry over his lost brother for the rest of his life, and he understood the stories now, understood how you were never the same once your parabatai died. He had always thought he and Jace would die together, that they truly wouldn't have to live without the other.
Now he thought that he had truly as good as died when he had killed Jace.
"It's okay," Magnus soothed, rubbing circles into his back. "You did what Jace wanted. You gave him relief, you gave him peace, Alexander. You did exactly what he would have done if the situation had been reverses," he assured Alec. And Alec knew it as the truth—if he hadn't before, he certainly did when Magnus said it; Magnus would never lie to him. Not about something like this.
And Alec knew then that he wasn't truly alone: he still had Magnus. Still had Magnus. And Magnus might not have been his parabatai, but God, Magnus knew Alec better than anyone else, was the deepest bond he had with anyone anymore. Magnus was his entire heart and what was left of his soul. Jace was gone, and with him he had taken a part of Alec's soul, his heart, but as long as he had Magnus… what was left of his heart could keep on beating, somehow. He could continue to exist—to live—to fight—to lead—to love. As long as Alec had Magnus, he knew, someday, he could come out from Jace's death mostly okay.
"I love you, Magnus," Alec choked out between sobs, when he could say anything at all. And it wasn't everything he needed to say, all there was to say, but God, it was all he could manage to get out for now, so it would have to suffice.
"I love you, too, Alexander. Always," Magnus promised easily in return, tightening his grip on Alec. And some of the tightness in Alec's chest loosened ever so slightly at that.