Jace had fought before, many times. He knew the chill of battle as it descended, the world around him slowing to a whisper, every movement he made precise and exact. Some part of his mind was able to push away the blood and pain and stink of it behind a wall of clear ice.

But this wasn’t ice; this was fire. The burn that coursed through his veins drove him on, sped his movements so that he felt as if he were flying. He kicked the headless corpse of the Dark Shadowhunter into the path of another, a red-clad figure flying toward him. She stumbled, and he sliced her neatly in half. Blood erupted across the snow. He was already soaked in it: he could feel his gear, heavy and sodden, against his body, and could smell the salt-iron tang, as if blood infused the air he was breathing.

He neatly jumped the dead Endarkened’s body and strode toward another of them, a brown-haired man with a tear in the sleeve of his red gear. Jace raised the sword in his right hand, and the man flinched, surprising him. The Dark Shadowhunters didn’t seem to feel much fear, and they died without screaming. This one, though, had his face twisted with fear—

“Really, Andrew, there’s no need to look like that. I’m not going to do anything to you,” said a voice behind Jace, sharp and clear and familiar. And just a touch exasperated. “Unless you don’t move out of the way.”

The brown-haired Shadowhunter darted hastily away from Jace, who turned, already knowing what he would see.

Sebastian stood behind him. He had arrived seemingly out of nowhere, though that didn’t surprise Jace. He knew Sebastian still possessed Valentine’s ring, which allowed him to appear and disappear at will. He wore red gear, worked all through with gold runes—runes of protection and healing and good luck. Gray Book runes, the kind his followers couldn’t wear. The red made his pale hair look paler, his grin a white slice across his face as his gaze scanned Jace from his head to his boots.

“My Jace,” he said. “Been missing me?”

In a flash Jace’s swords were up, both tips hovering just over Sebastian’s heart. He heard a murmur from the crowd around him. It seemed that both the Dark Shadowhunters and their Nephilim counterparts had paused their fighting to watch what was going on. “You can’t actually think I missed you.”

Sebastian raised his eyes slowly, his amused gaze meeting Jace’s. Eyes black like his father’s. In their lightless depths Jace saw himself, saw the apartment he had shared with Sebastian, the meals they had eaten together, jokes they had traded, battles they’d shared. He had subsumed himself in Sebastian, had given over his will entirely, and it had been pleasurable and easy, and down in the darkest depths of his treacherous heart, Jace knew that part of him wanted it again.

It made him hate Sebastian even more.

“Well, I can’t imagine why else you’re here. You know I can’t be killed with a blade,” Sebastian said. “The brat from the Los Angeles Institute must have told you that, at least.”

“I could slice you apart,” Jace said. “See if you can survive in tiddlywink-size pieces. Or cut off your head. It might not kill you, but it would be fun watching you try to find it.”

Sebastian was still smiling. “I wouldn’t try,” he said, “if I were you.”

Jace exhaled, his breath a white plume. Don’t let him stall you, his brain screamed, but the curse of it was that he knew Sebastian, knew him well enough that he couldn’t trust that Sebastian was bluffing. Sebastian hated to bluff. He liked to have the advantage and know it. “Why not?” Jace growled through clenched teeth.

“My sister,” said Sebastian. “You sent Clary off to make a Portal? Not very clever, separating yourselves. She is being held some distance from here by one of my lieutenants. Harm me, and her throat will be cut.”

There was a murmuring from the Nephilim behind him, but Jace couldn’t listen. Clary’s name pounded in the blood in his veins, and the place where Lilith’s rune had once connected him to Sebastian burned. They said it was better to know your enemy, but how did it help to know that your enemy’s one weakness was your weakness too?

The murmuring of the crowd rose to a roar as Jace began to lower his blades; Sebastian moved so quickly that Jace saw only a blur as the other boy whipped around and kicked out at Jace’s wrist. The sword fell from his right hand’s numb grasp, and he threw himself backward, but Sebastian was faster, drawing the Morgenstern blade and slashing out at Jace with a blow that Jace managed to evade only by twisting his whole body to the side. The tip of the sword sliced a shallow gash across his ribs.

Now some of the blood on his gear was his own.

He ducked as Sebastian slashed out at him again, and the sword whistled past his head. He heard Sebastian curse and came up with his own blade swinging. The two clashed together with the sound of ringing metal, and Sebastian grinned. “You can’t win,” he said. “I’m better than you, always have been. I might be the best.”

“Modest, too,” Jace said, and their swords slid apart with a grinding noise. He moved back, just enough to get range.

“And you can’t hurt me, not really, because of Clary,” Sebastian went on, relentless. “Just like she couldn’t hurt me because of you. Always the same dance. Neither of you willing to make the sacrifice.” He came at Jace with a side swing; Jace parried, though the force of Sebastian’s blow sent a shock up his arm. “You’d think, with all your obsession with goodness, that one of you would be willing to give up the other for a greater cause. But no. Love is essentially selfish, and so are both of you.”

“You don’t know either of us,” Jace gasped; he was breathing hard now, and knew he was fighting defensively, fending off Sebastian rather than attacking. The Strength rune on his arm was burning, flaring up the last of its power. That was bad.

“I know my sister,” said Sebastian. “And not now, but soon enough I’ll know her every way you can know someone.” He grinned again, feral. It was the same look he’d worn so long ago, on a summer night outside the Gard, when he’d said, Or maybe you’re just angry because I kissed your sister. Because she wanted me.

Nausea rose up in Jace, nausea and rage, and he flung himself at Sebastian, forgetting for a moment the rules of swordplay, forgetting to keep the weight of his grip evenly distributed, forgetting balance and precision and everything but hate, and Sebastian’s grin widened as he stepped out of the way of the attack and neatly kicked Jace’s leg out from under him.

He went down hard, his back colliding with the icy ground, knocking the breath out of him. He heard the whistle of the sword before he saw it, and rolled to the side as the Morgenstern blade slashed into the ground where he’d been a second before. The stars swung crazily overhead, black and silver, and then Sebastian was standing over him, more black and silver, and the sword came down again, and he rolled to the side, but he wasn’t fast enough this time and he felt it drive down into him.

The agony was instant, clear and clean as the blade slammed into his shoulder. It was like being electrified—Jace felt the pain through his entire body, his muscles contracting, his back arcing off the ground. Heat seared through him, as if his bones were being fused to charcoal. Flame gathered and coursed through his veins, up his spine—