Who cast the first spell would be decided later on, mostly at the trial in the Ministry a month later.
Who cast the last spell, on the other hand, was most certainly more easily guessed at. "Imperio!" the shouted Unforgivable slammed into the dueling blond haired teenager and nearly knocked him off of his feet, and it was at much length that his wiry and twisting mind succumbed to the unknown caster's will.
The other two, both colored by brilliant auburn hair of varying lengths, stood panting in the other two positions of the unwittingly made triangle as piercing blue eyes spread over the area in search of who had appeared.
His younger and far more sensible brother took the opportunity to punch him in the nose to the crunch of cartilage breaking and a steadily spreading spray of crimson fluid before marching sharply over toward their cowering sister.
Or so she had seemed just moments earlier, not ten or fifteens seconds before when the three-way duel had erupted, but now she was calmly composed and sitting on her knees in a manner unlike any that he had ever seen her react with toward magic since the incident.
For one terrible moment Aberforth Dumbledore suspected their sister was brain-damaged by a wayward curse. It was about that point that the intruder in their argument put that concern to rest.
"She's fine. I put her to sleep before I took over Grindelwald." Said the man, for he was plainly so, given the longish black hair, gaunt green eyes, and beyond-the-times choice of clothing in addition to an unsightly inflection of black dots along the jaw and cheeks could hardly have been a teenager.
He also gripped a very long white wand in one hand, and a more care-worn brown wooden one in his other. Aberforth scowled furiously as he examined him and the paused foreigner standing with the typical frown tugging at his features a few feet away.
His brother Albus recovered from the unexpected blow to his face and finished patching up the worst of the damage, and then he looked at the adult wizard and felt a thrill of emotions race down up and down his spine.
The nearest he could settle down on was something of gratefulness, and he opened his mouth to begrudgingly thank the stranger when Grindelwald twitched and for a moment brought his own wand up into the air in the unmistakable motions of a very dangerous fire curse.
A low bang! echoed around the clearing as said wizard was disarmed and slammed into a tree, adding insult to injury as his wand-arm was dislocated.
"Save it for the trial, Albus," the man said in a different tone to that which he had reassured Aberforth with, a biting snap. Albus stood up a little straighter as his eyebrows knitted together in a more easily defined anger and only just kept from brandishing his own wand with it.
"Aberforth, if you'd be so kind as to gather Grindelwald's wand for me, there's a good chap, I believe we can set this averted train-wreck onto a proper course." The man requested in the same return to a softer tone.
Slowly and warily the younger Dumbledore brother did so and it was as the man was distracted watching him that Albus struck. His wounded pride, not only at being down-dressed in the ideals of the Hallows by his own idiot of a sibling, but also being almost coldly addressed by this no-body was too much to accept.
He vanished in a crack of Disapparation and reappeared some feet away and in the air, dropping a good twenty feet but confident in his aim nevertheless.
The ground rose up as if to swallow the intruder and formed a cage of dirt and root and rock, pressing in on the man to subdue and contain him. Confident that his will had been successfully enforced, Albus twisted about to Apparate away.
He found his body unresponsive. A second later and he hit the harsh ground for himself, only barely getting up a nonverbal cushioning charm in time to delay the worst of the pain from such a fall.
Aberforth looked down on him with disgust, then directed a well-aimed kick to Grindelwald's face and for the second time that afternoon broke someone's nose.
The walls of earth and what-have-you that Albus had called into form began to bleed and peal back, revealing a dirty haired and grime coated, slightly bleeding adult wizard in otherwise healthy condition.
The cage that had been intended to contain him was slowly transfiguring itself into a variety of earthen toned plants and insect life as the dark stained wand slowly twirled through the air.
"That was a very, very bloody stupid move. I just wrested control of a man whose mind is considered to be your equal, Dumbledore, and you still thought it safe or creative to try and entrap me? Merlins beard, you're supposed to be the smartest wizard of this generation!" the man scolded him harshly as he finally stepped up and out of the work of art left in his wake.
Aberforth felt, for the first time in a very long time, the beginnings of a smile rise up as he listened. He would step in if he thought Albus was in serious danger, but he had little doubt that it would do much good.
"Stop wallowing in the dirt and come stand with the rest of us lowly mortals already, Dumbledore." The man ordered with an unmistakable distaste, stowing away his cleaner wand in a holster attached to that wrist and forearm.
If looks could kill, than most probably everyone standing nearest would have been struck down on the spot, including their aging neighbor Bathilda Bagshot, who chose that moment to react to all the noise by waddling over to the fence and looking across.
"Good heavens! What is- Gellert!" her initial concern at the scene changed rather easily to one for her nephew at the sight of his slumped and bloody faced form resting against the base of the trees nearby.
When he didn't stir to his name being called she gave a misty eyed sniff and quickly pushed her way around the bushes and to the gate, swinging it open and hurrying toward him.
She spared the other adult wizard a look of confusion over his apparent lack of concern for the blood, then paused as she saw young Albus laying in the mud and the mystifying transfiguration not much farther along.
The stranger filled in some of the details rather conveniently, saying, "They had a bit of a test of their magical prowess, and I'm afraid it spun out of control when Ariana and Aberforth stepped out to watch- you know how it gets around excitable Quidditch players, yes? A bit more effort to outdo one another with an audience?" he lied remarkably smoothly, his tone and expression conveying just enough concern.
Bathilda looked back to her nephew with heavy eyes. "But why is he slumped like that?" she asked him nervously, only the rise and fall of Grindelwald's chest keeping her from rushing over any further.
"I had to patch up the nearest and more grievously injured of the two, and was just about to help him once I was through with Albus here. Isn't that right?" he added toward Dumbledore while extending one hand to lift the boy to his feet, green eyes boring into enraged and calculating blue.
Aberforth answered when it seemed Albus would do nothing of the sort. "Aye, ma'am. We were just wanting a proper look at their skill, and it flared more powerfully than expected." He affirmed the lie in his usual, partly demure and quiet tones, just enough anger apparent to indicate his frustration at the way it had turned out.
The dark haired man leaned over and gripped Albus free hand between both of his own and, with a grunt, drew the auburn haired wizard to his feet. "Why don't you take your family back inside while I have a chat with Mrs. Bagshot, Albus?" he suggested with a flat imitation of a kindly smile.
His worn wand was by now sticking up out of the sophisticated looking belt, but Albus warily trotted over to his sleeping sister and lifter her up into his arms with a levitation charm and hurried inside of the front door, allowing it to slam shut before Aberforth could even step forward to follow.
Bathilda looked back and forth between them in concern, and the stranger allayed her once more. "Alas," he said quietly, "I think his pride took as much damage as his body. Well!" smiling more genuinely, he looked at the old woman and said in a pleasanter tone, "Shall we go and have a look at your nephew?"
She nodded as Aberforth wandered over to the porch and sat down, having no interest in hearing Albus fume or the confrontation that would no doubt follow, but most assuredly curious and still unsure about the unknown man.
She was unprepared for the almost silently whispered "Obliviate!" that followed as they stood over Grindelwald's body, and the follow-up stunner insured she was out of the way. He levitated her back over the fence and into her house, where she was left sitting in her armchair and the small table before it still lined with pages about her up-coming book.
After that was done the older wizard staunched Grindelwald's bleeding but left the younger wizards nose smashed in, then drew the other wand again and pushed Grindelwald to march over to the house.
Quite a few minutes later and the lot of them were gathered together inside of the Dumbledore's living room, or what counted toward it for the time- the kitchen. Ariana was still slumbering easily in her small room, while Albus stood at the head of the table where once his father, and later mother, had often sat at as the head of the family.
Aberforth was beside him to the left, while Grindelwald was slumped across from him. The as of yet unnamed stranger sat in a conjured and remarkably more comfortable looking chair overflowing with red pillows.
He gestured with his plain looking wand, giving the right to speak rather rudely to Albus seeing as it was already so being his home, and the older of the two brothers managed to keep from doing something about it only due to his brief time to vent into a letter after stepping inside.
"What do you want?" Albus demanded in a poor imitation of the calmness he might yet learn to radiate in his eldest years, leaning the palms of his hands along the edge of the table without sitting down.
"Why have you interfered in the duel, and better yet where do you come from?" he continued to ask, "I have been in correspondence with many of the names of the current day, and not once in my references have I ever heard mention of a man like you."
The other adult wizard nodded at the questions and answered in a better tone than he had yet addressed Albus with, in reverse order. "I have spent the majority of my time in seclusion due in part to the gift my great aunt awoke within me during my youth, the Seer's Inner Eye." He said simply.
"It has not been an easy trip to get here, considering the multiple paths the Eye revealed as being possible should certain outcomes be met. I fear that if I had not intervened at the time that I did, one of your four would have died, and two others set upon a path of mutual destruction for the years ahead." He explained in a passable imitation of truth.
"Thus," he paused to look at them more seriously, and then to Grindelwald in particular, he said "I have chosen to take the least likely of the paths I have foreseen to prevent such a tragedy from occurring. If you continue to haunt after the Hallows, I will be forced to dissuade you, for nothing good can come of their union- on the opposite, if truth be told."
Albus blue gaze was not only skeptical, but critical. "You have some degree of proof for this rather large pile of Thestral waste?" he requested in a far more flat tone.
The man nodded. "You have told no one but your brother and Grindelwald of your plans to utilize the Hallows for the 'Greater Good', enslaving all of muggle-kind and presenting yourselves as the two equally placed overlords of a new wizard dominion."
"You know that Grindelwald desires to use the Resurrection Stone for creating numerable Inferi armies, despite the fact that it can only call upon shades of the human soul from that which exists beyond. You would yet take up the Wand if you could with so much ease, and happily demonstrate its skill in a way that no other wand could flourish for you."
"But," he paused at last, and the air in the room cooled noticeably as the windows darkened and a fell wind rustled their hairs, "if you dared to take up these objects and worked together with Gellert Grindelwald, I can promise you that there are those alike myself stationed throughout the world who would rise up and eradicate you." He swore quite easily.
Albus reaction to the words was to take command of the household magic and the ancestral wards his father had wrought, and his mother had brought to this house, to hold the stranger in place and do something about his condescending attitude and tones.
Like unseen, ethereal chains, the Dumbledore's magic enshrouded himself and caused his power to quadruple, to nearly quintuple, and when he spoke his words caused the windows and other silverware and glass to rattle on the brink of destruction.
"You have come unbidden to my home, and insulted me time and time again. You have endangered my ideals, and threatened to destroy what can, and must, be done before the muggles can ruin us. NO MORE! Begone from my home, my village, and my world if I could so enforce it!" he very nearly shouted.
The power of his voice dissolved the conjured chair and swept the other man back against a wall, holding him there and piercing through the old concrete in flickering waves.
Aberforth had never seen it done before, and he was briefly awed by the effect before he saw exactly how much damage was being reaped against the unknown man; his flesh was rippling and drawing free of his underlying muscles, giving a bizarre and distended look, and flakes were drifting free to waft down the hall.
"What are you doing? You're killing him!" the younger brother objected, standing up. Albus gestured and he was pushed back down and against his seat.
"What must be done for the Greater Good." Albus echoed the anthem he would yet repeat if the future was not changed, if he truly marched forward at Grindelwald's side and united the Hallows against the world.
Despite this and the power destroying the other wizard, the stranger managed a mangled grin and sagged into the concrete obediently.
This is what Ascension of an Empire originally started off as, a time-travel fic in which the Empire had already been built and was trying to be halted by future generations of wizards in opposition of it. I scrapped this concept and decided to work on building things up first, so while this could yet happen, it would only happen quite some years from now after Empire was concluded.