REMORSE
"Severus…"
The terrible pleading sound touched his ears lightly as a predator's breath on its victim's neck. The moment has come. He pushed the foolish Malfoy boy out of the way. He'll show him how it's done properly...
Then he realized he was the predator. He gazed at Dumbledore, suddenly wishing he wasn't the owner of the body he currently inhabited. He hoped beyond hope that somebody would stop him.
Why did he have to do it? How did he ever find himself in this position? In this very moment he wished he would have never saved Dumbledore from the cursed ring. Why did the old fool have to summon him? Why didn't he just roll over and succumb to the curse? It would have been so much simpler.
He was also to blame, he knew that perfectly well. He regretted he ever agreed to be bound by the Unbreakable Vow with Narcissa. He cursed himself and his weakness over and over again, but what was done was done. Unbreakable Vows could not be broken.
He was the one who saved Dumbledore's life and now he will be the one to take it.
"Severus… please…"
How he hated the word! And how he loathed the old man for throwing it pleadingly at him! And how he disgusted himself for complying with it!
He had to do it. The fiery threads of the Unbreakable Vow burned him as fresh as new. They slithered up his arm, into his chest, into his ears, whispering...
He was afraid his hands might start shaking, afraid that his secret might be discovered at any moment, afraid that he will die for not complying with the Vow had he delayed it a bit longer.
Do it. Do it, or you will be the one to die.
It's either him or me.
He told you himself to do it. He begged you.
He watched his hand in dread as it lifted the wand and directed it at the old man.
He will die anyway.
You promised.
You promised you would do anything.
...
"Avada Kedavra!"
...
To his horror his wand obeyed the demand. He watched in disbelief as Dumbledore collapsed under his curse.
There.
It's done.
He could feel the stares of disbelief on his back. They didn't believe him capable, did they?
Who's the coward now?
Yet he did not feel courageous. He did not feel anything remotely similar. He cowardly feared for his own life as he yelled those two words.
You're a bloody coward!
Realization drowned on him as he lowered his wand.
What have I done?
He could swear he heard the sound of his soul ripping apart. His insides were screaming, they were screaming so loudly he was afraid somebody might hear him. He would have collapsed, would have roared in remorse, but there was no space and no time for that. He would have to bury it in the murky depths of his mind.
It was him. It was his hand, his voice, his curse. Now he was not only a coward but also a bloody murderer!
Why did his wand always have to do what it was told? Why did his hands always have to move the way he ordered them to move? Why did his voice never falter? He wanted to tear his miserable self apart!
He hated being himself. It was revolting to have his skin covering him.
Strange muffled silence engulfed his ears. He was aware if his surroundings, aware that his legs were moving, aware that he grabbed the foolish Malfoy boy and pushed him forward. He was strangely aware of everything his body did, yet he could not feel his limbs anymore. It was as if it was not his body at all. He was numb, cold as a stone. He was nothing but a hollow armour sent into the battle to do its master's biding. Imagining himself empty was the only way to prevent his chest exploding with guilt and shame.
Dumbledore's body fell over into the depth, and he would never see him again. He was grateful for that. He couldn't bear to see him lying there, cold and lifeless, a strong reminder of his terrible sin. Yet, still, whenever he closed his eyelids he could see those tired blue eyes, and he could hear those words, pleading for deliverance.
He knew from the very beginning that the green flash of light would never leave him. He just didn't know how much the remorse would hurt.