There was a fundamental change in Dumbledore's demeanour and looks. When life returned to Hogwarts no one seemed to notice and if they did, he couldn't tell. The staff treated him as they always had and so did the students. This superficial normalcy filled him with a sense of control that didn't live past the school year. It was an unfortunate, unforeseen event that crushed it: the escape of the rat-like man.

Dumbledore spent that year testing the possibilities of his new seer abilities, a power bestowed by the darkness within the dagger. Much in the fashion of Gryffindor's sword the dagger absorbed the power of those killed by it and one of his predecessors had seen fit to kill an extraordinary seer in his own quest for control over fate. He knew he had to avoid the use of this cursed power, he had Zoso's memories; the man had little of man left in him by the time he'd put himself in the deep slumber of a dreamless sleep curse. It was the only way to halt the darkness from taking hold, once it filled the vessel's heart they would die. This outcome was unavoidable, at some point the tainted human soul of the vessel would get crushed and a true lord of darkness would rise in its wake. It was laughable, really, that someone as trivial as Tom Riddle would dare give himself such a title; the dark lord was a wizard not even a hundred years old who's only dabbled in dark magic found in written word. The last time a dark one raised to his full power was stored in his collective memory now, clear as yesterday, but long forgotten in both wizarding and muggle history. It happened during the period fittingly called 'dark ages' and lasted for a thousand years; his reign ended as all do, by a wizard mad enough to take hold of the dagger and stab his heart with it, thus restarting the process.

The old wizard had sworn to use the darkness for light, to keep it at bay as long as possible. And in his first dabbles he'd found himself with an outcome not quite like what he saw in his visions, but with all the same pieces fitting in like a faulty, confusing puzzle. Divination wouldn't aid him in his quest as much as he'd like hence going forward, he used it sparingly, getting only hints of vital events and pieces of knowledge useful enough to manoeuvre through what lay ahead instead of directly trying to meddle with the future. Let the events unfold themselves, he decided.

It was in Harry's fourth year that he got a glimpse of Voldemort's return; in trying to prevent it the previous one he had only pushed it forward. This time he'd let it happen, albeit knowing how, twisting events enough to still be in relative control: Harry would be protected when he faced Riddle, that much he knew he knew. Diggory wasn't so lucky. The boy wasn't in his vision anyway, his death was an unsavoury thing but so was war, he couldn't dwell on single lives when the world was at stake.

During fifth year his character change was more obvious, but he was able to blame it on the need to distance himself from the boy so as to not trigger the ministry's response. The boy was loud enough on his own, preaching of Voldemort's return to anyone who'd listen. Dumbledore's relentless search found him immersed in finding Riddle's horcruxes. He knew now the diary Harry destroyed in the chamber of secrets had been one and it wasn't the only one; little peeks into the future showed him images of relics, a locket, a ring in his hands and some others in the boy's possession, but he was a bit older then. Two years at the most, he reckoned.

"I lost my head, Harry" he said to the boy, excuse as to why that summer before his sixth year he'd pun on the cursed horcrux ring and was brandishing a blackened hand. But it wasn't true. He'd put it on because he'd seen himself do it, because it was how it was always supposed to be. In doing otherwise he'd be meddling with time again, with unforeseeable consequences. This way he could control the time stream and make sure it flowed in the right direction, his preferred direction. It was a dangerous course of action but he was set on it. The moment the horcrux magic got into his body, the dark curse absorbed it and spread like fire on wood. The colouring of his hand was the telling tale, it turned black and a bit scaly, the colour of his dark one's form to be. The cursed shade would creep upwards and once it reached his heart all would be lost. But in his visions he saw, someway, this would end in Riddle's demise; his ultimate goal. Dying was an obligation now, for it was clear he didn't have enough time left in him; Voldemort's attack was too far away.

So, he'd leave.

But someone had to take his curse at the proper moment, another vessel. A compulsion drove him, a magical pulse as dark as the curse, compelling him to strike a deal, to seal the fate of the dark one in a self-preservation chess-like move. All he could do was turn the evil coercion in his favour, if only a little bit, and he expelled it in the form of an unbreakable vow.

"You must be the one to kill me, Severus, it is the only way".

And it was, for only an extraordinary wizard of both power and mind would be able to continue his work and carry the curse. Snape had both and he would see the plan through, forfeiting his life if necessary. There was light in him despite dabbling in the dark arts and it was his strongest asset. Albus knew his love for Lily prompted his change to the light but his loyalty had a greater purpose now, he wouldn't stray off course. Severus would not succumb to the pull of the dagger, no.

"And my soul, Dumbledore? Mine?"

"You alone know whether it will harm your soul to help an old man avoid pain and humiliation" said Dumbledore, speaking like one would to a child.

After an expected back and forth they struck the deal. Snape's bark was stronger than his bite. He made the vow knowing the dark lord would ask this of him anyway; when Draco's resolve faltered the task of killing dumbledore would fall upon him. In this moment he wondered why the old wizard was asking a vow of him, as if he could do anything but; He had backed himself into a corner after all his years of toying with loyalty and spying. But he didn't have much time to ponder on it because once the dubious deal was sealed, Dumbledore finally shared his true tale.

"What do you mean I won't kill you for the dark lord? You've condemned me to death if I don't!"

"Whether you have to take my life or not is another matter entirely. You can fulfil Draco's duty without doing so. It all comes down to…this" Dumbledore said, putting his hand into his robes to retrieve the dagger. With a sombre expression he turned it horizontally so Snape could read the name carved in it.

"What is this now, Albus? That thing reeks of the darkest magic I've ever seen, not even the dark lord" His voice faltered.

"That is precisely the goal, my boy, to keep the dark lord from its grasp"

The evening took a turn Snape would never have envisioned, not in his wildest dreams. The old fool started spinning a tale about an ancient relic long forgotten; the dagger, somehow created with Nimue and Merlin and passed through the ages from vessel to vessel. Those who wielded it possessed power over the darkest of magics, the cursed thing was both the strength and weakness of the vessel. He was grinning at this point, Dumbledore had become, in his quest to stop the dark lord, the darkest of dark wizards; oh, the irony was not lost on him. And when he was told that in his ambiguous vow, he had unknowingly pledged himself to be the next vessel of the curse all he could do is laugh, maniacally laugh at the man, at himself and the fates that had driven his life to this end.

"Has it ever crossed your brilliant mind that I can't do this? You can't do this!" He scoffed angrily "You're telling me you've had this curse on you for three years and we're hoping you last through it one more, before becoming something that'd make the dark lord look like a dim-witted infant with a twig for a wand, and you hope I absorb this thing in me and do what with it? That is, assuming I'm even able to resist the pull of the darkness immediately after. You've clearly lost your mind old man!" Snape was livid.

"Now Severus, there's no need for any of this. There are ways around the curse, one can voluntarily hide while in deep slumber, just like Zoso did before me. All of this you'll know when you take the curse, there's thousands of years of collective knowledge and memories in it. Passing this power is the best chance we have to shield it. Think, if I was able to locate it so would have been Tom. He's in a quest for immortality and power, it was only a matter of time. Now unknown to him or not, this power would have crossed his way and he's not one that hesitates from taking raw power, unlike you're showing yourself. And what do you think would happen then? Do you see him resisting the pull of the dagger? No, he'd be one with the darkness within seconds, the shrivel of a soul that's Tom's would die instantly. This power would grant him rule of the world, that he so craves, only it wouldn't be him ruling but an entity of pure darkness; a new dark age would fall upon us. The dark one's existence and its identity must remain hidden from Tom until his demise and then, made long lost and forgotten once more.

Dumbledore's plan was anything but simple, the discussion made one thing clear: killing him wasn't a fate set in stone, it was built-in as a fail-safe. The vow didn't require an absolute death from him, perks of his short-lived status as an immortal being. Falling deep in a sleeping curse, that he could do. They'll make it seem like he was killed; he could be hit with Avada's at discretion and not lose a single hair of his beard anyways. And the plan was set in motion, right after faking his death Albus would take a simple sleeping draught brewed by Snape and sleep only long enough to fool everyone. He'd put in place a body no one would doubt was his and let them mourn him, while his true body would rest in the dark one's vault under the strongest draught of the living death Snape could brew. The dagger would remain hidden because in the unlikely event that Voldemort triumph was imminent and no other option remained, Snape was to take the dagger and plunge it into the old wizard's heart, acquiring his cursed power while somehow resisting the pull of the darkness and with it, banish the discounted dark wizard after his few minutes long reign, retire to the dark vault and rest in eternal slumber himself, hopefully sealing away the power of the dagger forever this time.

Piece of cake, Snape thought.