"What are you doing here?" Clary panicked, scrambling, pushing herself against the back of the bed.

Am I dreaming…?

Clary could not see him properly, only the solid black outline was visible. Then, he slipped into the moonlight. The stream of pearl grey light illuminated his pale hair and kindled a single black eye that stared down, rapt, trained on the sleep-rumpled figure of his sister. Clary resisted the impulse to conceal herself from his intrusive gaze behind the covers. No, she told herself, I won't shrink from him.

Then, he made a sound, not a word. Just a meaningless noise that issued from between his lips; something, Clary had thought, should have been unknown to him. It was a tender sound that comforted, that said, I am here. She could not imagine a small Sebastian, whimpering into the crook of her stone-shouldered father's neck, and Valentine tilting his head towards the little thing, caressing, and pursing his lips in the way Sebastian was now. "Ssshhhh….." It seemed to go on for a very long time. After a long pause, it was followed by a whisper, "I'm not here to hurt you."

"How did you get in here?" Clary's voice shook with anxiety, trying to remember where she'd put her seraph blades.

"Does it matter? We both know, by this point, what I'm capable of. If I want to speak to you, Clary, nothing will get in my way. I won't keep you long, I promise."

"What do you want?"

She watched his eyes rake around the room. "I want to exact a promise from you,"

Puzzled, she repeated, "A promise?"

"Yes." His eyes returned to claim her attention, and she felt a shudder run through her. She thought the same worn-out question she'd stirred over in her mind, over and over, hundreds of times before: how….how can it be…that this boy is my brother? "I want you to promise me…" he began, "if I die tomorrow…you'll bury my body. Honourably. As any Shadowhunter is entitled to. Inter my ashes with the Morgensterns."

Unintentionally, Clary let out a derisive sound. "You've done everything you can to ensure that you don't deserve the name of Shadowhunter. You have done your utmost to destroy us. Of all the Shadowhunters you've hurt or killed, of all the despicable things that you've done…there isn't a single one that would object to seeing your rotting corpse cut into pieces and tossed to the bottom of Lake Lyn,"

Sebastian let out a tired sigh. He moved, sitting on the edge of Clary's bed. Clary squirmed backwards. "And yet," he said, "They allowed that much for our father."

Our father. Our. Father. Clary detested that pronoun, that incontestable declaration that she, with this monster, shared genes, shared a father. "No," she replied, "They did that much for Valentine because, ultimately, he never wanted to destroy the Shadowhunter race; he wanted to help them. Even when…even at his worst, he never surrendered his allegiance to Shadowhunters."

Sebastian was silent for a moment. "But he went about it in the wrong way? So it's methodology, then? Do you think if I tried destroying things quietly they'd give me what I—"

"No." Clary's voice was flat. Merciless. "That's where we draw the distinction between you and he. You are not a Shadowhunter. You never have been. You have no right to that name. You are not of angels; you are of demons. And you are evil."

"And still…I am your brother."

They were silent for a long while; while this unleashed truth made a ruin of Clary's mind, and like every time she thought about it, fury and disgust uncurled in her stomach, like a coiled snake unwinding, and slithering through her. "No. Blood means nothing. You will never, ever, be a brother to me."

"You are wrong, Clary." He said, with sudden ferocity. He leaned forwards and grabbed hold of her wrists, pulling her towards him without an ounce of gentleness. She let out a gasp. "Blood means everything. Your flesh is my flesh. Your blood is my blood. I am in you, Clary, whether you want to admit it, or not."

You have a dark heart in you, Valentine's daughter.

Clary felt her heart tug, as if the words called to her. "I wonder," he said, "if, tomorrow, you kill me, what will you say? When people ask you about me? How could you kill your brother?Will you deny me, as you do now? Will you be ashamed of me? Will you be glad?"

Clary could not form an answer for a few moments. Then she murmured, "I will tell them you were not my brother. You were an abomination."

Sebastian made a small chuckling sound and leaned back from her, letting go of her wrists. "So, then, who will be your brother? Jace?"

"Leave Jace out of this."

"No, Clary. Don't you ever think about what you would have done if you'd never found out about me? Do you think you would—what—be dutifully killing demons and making a misery of your life without him?" He made a rumbling sound in his chest and sneered. "No. You'd have run off somewhere and you'd be in his bed and happily wallowing in your sin. Don't act so self-righteous, sister. All your morals and principles don't mean much, in the end, do they? You tell me I'm soulless and evil and yet, Clary, you don't see. You can't see yourself: sitting here, telling me that you want to kill me, your own brother. Because it happens to be the right thing to do? Just like killing our father was the right thing? Don't you see?" His voice lowers to a whisper as he leans towards her. "You're exactly like me."

Clary jerked back, anger flaring. "No! I'm not! I know what love is; you don't."

Sebastian retrieved her wrists again, bringing her closer to him. "How could you know I can't love? You never gave me chance!"

"Get off me!" Clary struggled, pulling against his grip, ignoring the throbbing under her skin as he tightened his fingers around her.

"No, Clary. I'll touch you if I want to. You're my sister. I have a right to touch you. And you, me."

"No. No, you don't. Not like this."

"Then, like what? How do I please you, Clary? Like this?" He pushed her, roughly, backwards, and without anything beneath her, she fell against the sheets. He followed, and laid himself beside her. He inclined his head to her and his warm breath fluttered stray strands of her hair as he spoke, "All I wanted from you was this. Someone to cherish, protect, touch, confide in. Love, maybe. Someone to be like me. And that's so unnatural? So inhuman?"

"Like this, it is. Brothers and sisters don't do this, Sebastian."

"Perhaps not. Perhaps they do. I don't know. I don't care. And don't pretend you know any better, either, Clary. You would never have done what you did with Jace, otherwise. Tomorrow, dear sister, we'll be fighting to the death. I think we're beyond adhering to silly rules, now, don't you?" He released one of her wrists, and moved his hand into the air, slowly, down to her hair, gently brushing it back from her face. Clary felt herself go rigid, feeling the stinging repugnance of his touch as if it left a stain across her skin that would be visible for everyone to see. "You'd be a fearsome mother, Clary. I'd pity your children. What would you do if one of them turned out like me—"

"They wouldn't turn out like you—"

"Oh, but they could. Dead, or alive, I'm still your brother. I'm still inside you. Would you abandon them, like you have me? Like Jocelyn did? Disavow them without a thought? Without guilt?" He stroked her still, but his fingers dug deep into her hair as if he was thinking about bunching it in his fist, and ripping it from her scalp.

Clary swallowed uncertainly, feeling nausea rise in her stomach and her heart gallop in her chest. She wanted nothing more than to scream, or to feel a seraph blade in her hand so she could stick it into him. "If I tell you I'll give you your burial, will you leave?"

"As long as you keep your promise, yes."

She wondered if he knew there was no way she would honour a promise made between them.

Abruptly, Sebastian flipped away from her and Clary let out a trembling breath. He rose from the bed, and looking down at her, said, "Good luck in murdering me, sister. I wonder who'll do it. Who will be Cain…" he tilted his head to the side, "And who will be Abel?"

Clary turned her head to answer him. "Maybe we'll both die,"

A wry smile twisted his mouth. "I hope not. Jace would race into hell and resurrect me just to have his revenge in sending me back again,"

"Good bye, Jonathan," It was only after Clary said it, that she felt her cheeks sear in humiliation.

"Jonathan?" He repeated, puzzled. "Don't call me that." He leant down over her, again, and tapped a long finger under her chin, lifting her face. "If you survive, call your first-born son that. For all I should have been." With a sigh, he placed his cold, diabolical mouth to her forehead, and pressed his lips, once, as if he wanted her to carry a scar of this moment. Then, his gaze found her terrified eyes. "Kill me, if you like. Just let me have my fun, sis. It's all I have left in this world." His lips fixed on hers and he kissed her, softly, as Clary's heart seized in horror. He exhaled a sorrowful breath over her face as he got up, and left.