Blue fire cascaded from the end of his wand, sweeping an arc in the direction of the gathered Death Eaters. They screamed in surprise and scattered. Harry pointed his wand skyward. The full moon reached its zenith. Power rushed through him, tingling his nerves and overflowing his senses. The moon shuddered and extinguished into pitch black night.
Two of the Death Eaters fell before anyone could react. Fire flooded Harry's veins, boiling his blood and he thrust it outward, licking the ground into ash.
Voldemort's forces fled. His mask and hood having been blown off in the fiery blast, Lucius Malfoy stood, jaw to the floor as he took in the sight of a child beating the ever-loving shit out of Charmeuse Nott, separating the man's head from his spine.
Yeah, nope! Lucius was a pragmatic man. Voldemort was going to die tonight and he was not in the mood to stick around and risk his neck. Most of his fellow Death Eaters were in agreement.
"Retreat!" He screamed.
"No! Cowards! I forbid you!" Voldemort commanded, even as Potter swatted a Killing Curse out of the air with a tendril of solid blackness. The boy's gaze turned to Lucius. No, not a boy. Not a human. In the child's eyes, he saw the many faces of his victims. He saw death, destruction, misery. He felt the phantom itch of the Cruciatus tingle down his spine, the cold numb of the Imperius, and something darker, heavy yet weightless. He tore his gaze away and realized he was crying.
The boy - no, not a boy, a thing - was laughing. Unforgivables flew from his lips like words to a lover. Rudolph Rosier fell next, tripping over a headstone as a spell hit his shoulder. A swath of black devoured his body. Again Potter turned his unholy gaze to Lucius, the evil glow of his eyes shining in the dark.
Lucius was no coward, as the Dark Lord implied. He was not an idiot, either. He had a family and a nice life and with the Ministry in shambles, he was needed elsewhere. He could further their cause, he did not need to die. He turned on the spot and fled.
Voldemort cursed as he watched his cowardly forces vanish. The boy was good, better than he'd expected, his knowledge of the most profane magicks rivaled Voldemort's own. But Lord Voldemort had been at this far longer than the boy had. He had traveled the globe in search of arcane knowledge. He was a fully trained wizard and Potter was still a boy. There was no chance that he would fall again to his teenage foe. All of them would pay for their betrayal of him in this most important moment.
Potter and Barty were fighting. Barty, for all his skills, was a lousy duelist. He had considerable raw power but no finesse. Potter had erected a physical barrier between them using the headstones to block the bright blasts of the Killing Curse. Deftly maneuvering around the field, he trapped Barty in a thick patch of conjured quicksand. Voldemort joined the fray before Barty could get disarmed or worse.
Potter parried against him with no concern. There was a madness in him, a viciousness to his movements, each incantation snarled out through heavy breaths. He wielded blue fire like he had been born doing so, surrounding the battlefield in tight rows of curling flame.
Voldemort conjured water. A hurricane of swollen floods and a fierce storm flashing lightning around them. It crashed over the fire. Potter did not falter, a twirl of his wand brought forth a fiery flock of birds that tore at the clouds with their beaks.
Barty attacked again, and a swell of ink blackness crested over them like waves. They grabbed Barty around the waist and tossed him far into the air. As he came down, the blackness morphed into an open maw and swallowed him whole.
It was just Harry Potter and Lord Voldemort remaining, a trail of oozing bodies around them, some still alight with ethereal flame. The ground was soaked through with rain and blood and the eerie, faint red of the eclipsed moon stood as sole testament of their battle.
"That is Dumbledore's wand," Voldemort noted. They were at a stalemate, pacing in a circle. Predator staring down predator. He could feel the shadows licking around his heels, smell the stench of death in the air. "Is that how you have gained so much power?"
"It's mine now. It's always been mine, he was the one borrowing it. Just as this is mine too," he held up a hand, flashing a familiar onyx stone ring. The Gaunt ring. Potter's robe, an ugly thing patterned in intricate swirling symbols, shimmered and dematerialized, flapped in the wind, flickering the boy's body in and out of existence.
"You did not!" Voldemort roared, aghast at the thought.
"Yup!"
"Not even Dumbledore would allow -"
"Dumbledore had nothing to do with this," the boy said with a laugh. "He is not my mentor - was not. He's dead, by the way. We traveled to your cave. Neither of us was very impressed by your protections. When you ask for a blood sacrifice, you should set it to something with some weight to it. I've gotta say, I have not been awed by you and your minion's skill in necromancy. Barty really fucked up that ritual."