A high, cold voice, tinted with slight amusement, rose out from the darkness.
"You should know it is futile. I cannot be defeated by someone like you, Dumbledore."
"In that, you are wrong."
Albus Dumbledore's voice was calm as he came into view. He was clad in a simple dark red robe, a cloak of the same colour and black boots; also, atop his auburn hair was an old, tattered, pointy hat.
Albus searched the darkness where he was now. He had just descended a flight of stairs leading to one of the most obscure places in the whole of London: the secret catacombs of the Tower of London, where countless prisoners had been buried in the past. The room in which he had arrived was a circular one, dimly lit by torches set in four points, forming a square around the stony wall. Beyond the square, shadows hid everything, including he who Albus had come to fight.
"Show yourself, Marcus."
Albus' calm voice echoed through the room as he pulled out his wand. This was the same wand that had realised countless deeds, most of them worthy of praise, and yet, today it would have to prove itself.
Silence was the only answer he got.
After some moments of tense waiting, a dark figure at last came into view. Completely dressed in black robes and cloak, the figure stared from beneath the hood with cold eyes the colour of gold. A smirk was also visible.
"Please Dumbledore, I prefer to be called Lord Grindelwald. It is a more fitting title for he who will rule the world."
The moment Albus saw and heard Grindelwald, his insides were full of fury. This was the man who had brought a terrible war upon the world at large, who had dared to attack his school and bathe his hands with the blood of innocents, and above all, he was the man who had killed Helena, his fiancée that had been robbed from him too early.
My dear Helena, Albus thought, you were torn from my side by that maniac... As he gave you no mercy, I will give him none.
"I'm afraid, Marcus, that you will never be called that way again…" Albus said, his voice turning slightly colder. His keen blue eyes glared in full hatred with a fire very few had ever seen. And all those who had seen that fire had regretted it. His poise, however, was still calm and expectant, ready to spring in action.
Grindelwald's only answer was cold laughter that infuriated Albus even more.
When it died down, Grindelwald slowly removed his hood and drew out his wand. Grindelwald's blond hair was slightly visible in the dim light, as well as the small smile he was still wearing. The mocking was evident, and it repulsed Albus. His voice still had that cold amusement that filled Albus with wrath. Marcus Grindelwald thought of him as another pebble on his road, and that was going to be his downfall.
Albus was going to make sure of that.
"Enough of this," Grindelwald said softly, yet menacingly. "Let us do what we came to do. Ready, Dumbledore?"
Albus nodded in agreement and removed his hat, carefully placing it on the ground. Then he and Grindelwald held their wands in front of their faces, as if they were swords, and bowed. Each man's eyes never left the other's. As they arose again, both tall and strong like the titans they were, time seemed to stop. Electricity filled the air as their wills struggled and the rest of the world ceased to exist for them.
And so, the duel began.
Albus and Grindelwald immediately pointed their wands at each other and launched their first spells. Like dragons breathing fire, their wand tips exploded in green and red flashes of light, the jets rushing at amazing speed and then colliding in the air. The resulting explosion of two curses neutralising each other shook the entire room and made enough smoke and dust to rise over and cover the battlefield. Three times this was repeated, and three times the results were the same, and after realising the futility of this, both opponents vanished in a whirl of their cloaks.
Albus reappeared in the middle of the room. He was tempting Grindelwald to attack him with his best, and just as he expected, green light came from the right and behind him. He turned to face the curse.
"Reflecto!" He yelled, and in an instant a mirror materialised in front of him just before the light reached him. The green light smashed against the mirror, making it explode into a thousand tiny shards. They showered down in a rain of little reflections, but the magical mirror worked and the jet was bounced directly towards its source. The green light tore through the darkness to simply smash against a wall.
"Good," Grindelwald's voice reached Albus' ears. It came from behind, and no longer was there any amusement in it. "You are better than I expected, Dumbledore, but you cannot defeat me with some clever spells…"
Albus simply kept his stance. He couldn't afford to lose his concentration by answering him, so he simply waited, his wand at the ready. He didn't have to wait for long, though, as a distinct sound reached him: rattling and hissing.
Snakes were coming after him.
Four snakes came into view, all quickly slithering towards him and hissing menacingly, their rattles mocking him with their warning sound. He lost no time, though, as he knew a green light was coming, and pointed his wand at one of the snakes at the same time that he muttered an incantation. The snake shimmered in bright white for a second, hissing loudly as if in pain, and then it started to change; the snake grew legs and fur, its head and mouth growing as the fur turned white with black streaks. When the transformation was done, what was left in place of the snake was a badger – a hungry badger. It immediately viciously attacked the other snakes as Albus vanished away, green light coming from his left barely missing him.
Albus knew now was his turn to attack, and as he reappeared to the left of where the green light had come, he raised his wand and muttered "Flamma". From the tip of his wand, bright, orange flames poured forth, lighting the room and revealing a surprised Grindelwald. The flames, however, didn't torch Grindelwald as the Dark Lord had expected. Instead, they fell around him, forming a ring of sorts and setting up a perfect target for Albus to shoot at. Grindelwald realised just that a second too late, and was blasted against the wall by Albus' Blasting Charm. He fell to the ground.
Albus knew this was not the end.
Behind him the badger had finished killing the snakes and now was devouring them with quite some content. He approached the fallen body cautiously, his wand pointing directly at it. Grindelwald did not move, and a small hope actually rose inside him that perhaps his attack had been enough to knock him out. Albus also knew that he had to finish Grindelwald right there and then, and as he gathered determination to utter the hated curse, his eyes caught sight of Grindelwald's wand. It was pointing right behind Albus, and his lips were barely moving at all as they gave voice to a spell.
Before Albus could react or fire his curse, he felt a very hard thing impact his skull from behind. He fell to his knees, but hastily jerked his head up to see his now standing opponent. His eyes fell on Grindelwald, who was smirking and giving him a glare full of hate. He was pointing his wand at a stone floating at his side. It seemed to be covered in a dark substance.
MyBlood. Albus guessed correctly.
With a flick of his wrist, the stone shot at Albus, who was still defenceless, and hit him squarely in the face, cracking his nose in the process. Albus fell backwards, and the pain coming from his sore face and broken nose made it very hard for him to stay conscious, let alone concentrate. The blood gushing out didn't help at all.
However, he focused all his will on standing up because he knew Grindelwald could finish him at any second. He could not be defeated yet. He was the only one who had a true possibility of defeating Grindelwald. Managing a sitting position, he tried to get a firm grip on his wand, only to watch in horror as Grindelwald acquired it through a simple Expelliarmus.
All his hopes failed. He had failed.
Grindelwald laughed again, and this time it was a terrible laugh. Cruel and cold, it was the same maniacal laugh he had used when he dared to storm Hogwarts. And the look in his eyes, relish evident at the sight of a helpless opponent, had been the same when he had killed her.
I'm not dying now! Albus' whole self inwardly yelled as Grindelwald pointed his wand at his chest, but his mind gave him no answers about how to escape and the pain in his face was not making it any easier. Unexpectedly, the Dark Lord started to speak.
"You know, Dumbledore, now I realise it is a shame I have to kill you." At that Albus' eyes widened in surprise, but only for a second, after which they resumed their hateful glaring.
"And I'm saying that because you have been the first to ever hurt me. Whole Auror squads fell without even touching my hair, and yet you almost put me in an uncomfortable position. Most remarkable." Grindelwald's smirk was repulsive for Albus, and so he tore his eyes away from him and searched for something, anything, that could be of use. The only thing he saw was his forgotten hat, lying a few feet away from him.
"It is such a shame your power doesn't serve my noble cause," Grindelwald continued, "but only one of us can live. Farewell, professor... Avada Keda--!"
Much to Albus' surprise, his conjured badger had attacked Grindelwald and prevented him from using the Killing Curse. It had jumped over him from behind, surely because Grindelwald smelled like his snakes, and now the Dark Lord was struggling to take it away.
If Albus actually survived the duel, he would be grateful to that badger for the rest of his life.
Grasping this moment of distraction, Albus jumped towards the old hat. He didn't know why he did that. It was almost as if an invisible force compelled him to reach out for the hat, instead of trying to recover his wand. The hat was lying on its side, the opening facing Albus, and so his hand slid into it.
He grasped metal.
Behind him, Grindelwald had turned the badger back into smoke and was aiming at Albus' back. Without another thought, a jet of green light came from his wand, and it almost seemed to take the form of a green skull rushing at Albus ready to claim his life.
The battle was over. There was no escape now. Of that, Grindelwald was certain.
In one fluid motion, Albus rose to his feet and twirled around, his hand tightly pressed around the rubies of the hilt as he brandished the gleaming silver blade. This was Godric Gryffindor's old sword, a sword rumoured to be imbued with magical properties, and Albus turned it against the Killing Curse in one last desperate attempt to survive.
To his and Grindelwald's greatest surprise, the sword withstood the impact and even deflected the jet of light towards the ceiling. The sword was intact. Albus' hand was shaking alongside the sword's blade, but his fury brought him back to his senses and so he lost no time and lunged forward with a cry.
The sword met little resistance as it plunged deep into the chest of the shocked Grindelwald.
Albus did not move for a few seconds, his eyes intently fixed upon Grindelwald's own eyes. Grindelwald stared back no longer with coldness, but with fear and despair.
"How-How could this be?" Grindelwald gasped before collapsing to the floor and dying.
That was the same question Albus had always asked himself. How could ambition lead someone to kill and destroy? How could innocents die so easily, as if their lives did not matter? How could she have died when they had the rest of their lives ahead of them? How could all that be?
Sighing at his lack of answers, Albus slowly picked up his wand and the hat. In his other hand, Godric's sword rested. The blade was covered in blood as red as the rubies of the hilt, and Albus realised the sword had come to him in order to take revenge on Grindelwald for his attack on the school and the fallen students.
He then left the shadows of the catacombs and returned to the world as a new man.