The agreement was effectively a magically binding contract between Grindelwald and the wizarding world.
In exchange for his life after defeat, Grindelwald was required to spend the rest of his days within Nurmengard's walls unless he found a way to serve wizarding communities without targeting the Statute of Secrecy or seeking dominion over muggles.
For nearly fifty years he had remained inside Nurmengard, because he refused to change his ideals.
Yet this year he had chosen to act again, and in a way that looked disturbingly similar to before.
And still, Dumbledore could tell the contract remained in effect.
...
It was well known that Grindelwald was a natural seer, his gift manifesting through his right eye, which was silver.
He must have seen a way forward, Dumbledore thought, unsettled. But I don't understand why he would act like this if that's true. What did you see, old friend, to go so far to reach this future of yours?
Dumbledore sighed and dispelled Voldemort's magic trying to probe the school wards for what felt like the fifteenth time that year.
...
Throughout the year, while Voldemort possessed Quirrell, he had been trying to find some way to sink his claws into the Hogwarts wards and take them over.
But every headmaster since the founders had reinforced those protections and added layers to them. Breaching them was nearly impossible.
Arrogance always was one of his biggest flaws, Dumbledore mused as he considered the trouble his former student had caused while assuming none of the other professors were aware of him.
In truth, nearly half the staff knew.
And they were letting the fool believe otherwise.
...
Snape, Sprout, McGonagall, Flitwick, and Dumbledore were all involved in setting an elaborate trap for Voldemort.
Each stage of it was designed to be solvable by first-years while also being as harmless to them as possible.
Take Fluffy, the Cerberus guarding the trapdoor to the next test. The creature was well trained, commanded to attack adult wizards with lethal force, while it was meant to capture children who might enter instead of tearing them apart.
...
The final piece of the trap was meant to be different.
It involved an altered version of the Mirror of Erised, modified to trap souls like Voldemort's current state. That kind of alteration required time, so the mirror had been placed in a disused room while Dumbledore slowly worked through the necessary changes.
Dumbledore had also played on his old student's pride by having Quirrell set up a level in the trap as well.
That way, once the trap sprang shut, Voldemort would fall to his own overconfidence and finally be dealt with, at least until Harry could strike him down for good.
...
Voldemort himself was beginning to suffer real problems. Quirrell's body and soul were rejecting his presence more violently with time.
It forced Voldemort to drastically cut back how long he stayed awake, just to buy himself time.
Even that would only extend the possession by another month or two at most.
Knowing Hagrid's obsession with dragons, Voldemort devised a plan to learn the weakness of the irritating magical beast guarding the rest of the tests, because that was the only stage capable of forcing him to waste time and power to pass.
...
Meanwhile, Julian had his own frustrations.
He was researching organic forging, and he couldn't make meaningful progress. It felt like he was missing a key piece of understanding, something fundamental, and the lack of it was maddening.
Certain enchantments held in unstable, low-quality ways.
Others refused to take at all.
Some simply detonated mid-forging.
Wooden rings, for example, held water and fire enchantments in an unstable manner that made the results both low-grade and dangerously explosive.
And no skill-based or spell-related enchantment had successfully adhered to wood for him yet.
That was the part that truly bothered Julian, because he could feel, deep down, that it should be possible.
...
Bone rings presented an entirely different problem.
They came with built-in affinities to certain forms of magic, and Julian had to learn what each material would accept.
The carapace of the acromantula he had hunted earlier, for instance, seemed to have an affinity for curses and poison enchantments, but it rejected almost everything else.
Julian didn't restrict himself to magical creatures either. He experimented with normal materials too, fish bone, chicken bone, cow bone.
But every one of them had its own affinity, its own stubborn limitations.
And figuring those limitations out was tedious, a slow grind of trial and error that ate time and patience alike.