As powerful as she was, Mai was not yet capable of giving Voldemort a run for his money; she still needed time to grow into her abilities.
"Run!" Oleandra shouted as she swooped down. "I'll cover your escape!"
After all, it would not have been the first time one of Morgan le Fay's incarnations had bitten the dust after misjudging the gap between herself and an opponent. Overconfident in her abilities, Mai's predecessor had fallen at Grindelwald's hands when she challenged him for the Elder Wand.
"Lend me a hand!" Mai cried without bothering to turn around. "Together, we can bring him down!"
It suddenly dawned upon Oleandra that the reason Mai had burned all her bridges, the Fairy Rings leading to the rest of the British Isles, was that she had never once considered the possibility that she might lose. The evacuation of the sanctuary would have gone far more smoothly had she not left only one portal intact, and if it hadn't been for Oleandra's timely return, many people would have died…
Oleandra barrel rolled to avoid a flurry of Stunners from the forest below. She caught flashes of golden capes out of the corner of her eye; the Heliopaths were moving in position to encircle Mai.
"It's not worth it!" Oleandra yelled. "He's immortal! Even if we kill him, he'll just keep coming back! Now come on!"
"Then we just kill him again!" Mai snarled, raising a wall of earth before her to block a Killing Curse. "As many times as it takes!"
The flames of the roaring inferno devouring the sanctuary parted as Voldemort strode forwards, wand at the ready, almost as though the fires cowered before his very presence. Oleandra's pupils dilated slightly at the sight. Such was the precision of his control over the Fiendfyre that he could walk amongst the flames without fear of being consumed.
"Oleandra Greengrass," said Voldemort, his voice infinitely cold. "Unlike Harry, you have given me no end of trouble. It is truly a shame you are not the subject of the prophecy, for then I would already have won."
"You haven't killed me yet," Oleandra replied tersely. "Don't count your Basilisks before they hatch."
"That can be easily remedied."
For a seventy-year-old, Voldemort was surprisingly spry. In a flash, Oleandra pirouetted in midair, already anticipating the trajectory of his Killing Curse based on his wand arm, but before she knew it, she was tumbling out of the sky. As the ground rushed up to meet her, she realised Voldemort must have created a magical interdiction on flight around himself; an Anti-Flight Jinx!
Mai waved her wand, moulding a giant hand out of the earth to catch Oleandra before she could crash into the hard ground, but with an impossibly swift flick of his wrist, Voldemort sent a piercing blue beam streaking towards it, severing it at the wrist, and the earthen hand crumbled just as it was about to catch her.
Despite her reticence to use one of the Horcruxes in such close proximity to the main Voldemort, Oleandra had no choice but to resort to the cup's magic. She braced herself as she fell, gripping the golden cup tightly, and lake water swirled out from its mouth, cushioning her fall.
At the sight of this, Voldemort's nostrils flared, and Oleandra could not stop herself from giving him a small look of triumph as she leapt to her feet… and in that moment, he knew that she knew. Somehow, his greatest secret had been exposed. He had not yet had time to check on the other Horcruxes' hiding places, having only just been resurrected, but once the two girls before him lay dead…
"That's right, I know your little secret, Voldemort," Oleandra said with a cocksure smile. "Horcruxes… I must admit, that was rather inspired. You even placed a fragment of your soul inside my sister, did you?"
Voldemort's face twisted into a half-melted wax mask of wrath, his scarlet eyes blazing with fury. Somehow, Daphne must have let the secret slip, he rationalised. Unfeeling doll or not, he would make her drown in endless agony before he was at last satisfied… for let it be known that none had tormented Lord Voldemort more than he himself had tormented his own soul.
"Avada Kedavra!" he roared.
Never before had Oleandra known him to lose his composure to such an extent.
She snapped her fingers, and a curtain of Thief's Downfall rose before her, but the green beam burned through it and streaked through unimpeded, forcing her to dodge. Apparently, the power to strip away enchantments did not mean immunity to any and all spells, especially the unstoppable Killing Curse.
"Protego Maxima!"
Mai waved her wand as a flurry of multicoloured bolts of light flew at them from behind, repelling the magical blasts. The Death Eaters' and Heliopaths' encirclement was complete; there was no way out any more. Without the ability to fly, they were well and truly doomed.
"Before you kill us, would you mind answering one of my questions?" Mai called out, raising protective walls of earth around her as she spoke. "You didn't come here via the Floo Network, did you? No… you breached the Sanctuary's protections by other means, didn't you?"
Mere minutes after the Muggles had finished experimenting with firing their guns using Floo Powder instead of gunpowder, blood had started spurting from the gun's barrel; evidently, someone from the Ministry had attempted to investigate this unplanned addition to the Floo Network.
The moment the poor inspector had stepped into the emerald flames of their fireplace, the Floo magic had begun slowly and painfully forcing them through the narrow barrel at the other end. The gun had then been hastily ejected from the sanctuary, but clearly, something other than pulped flesh had come through…
"Something like a Portkey, say?" Mai deduced. "AccioPortkey!"
"Finite Incantatem," Voldemort hissed, but Oleandra was one step ahead of him.
Even Oleandra did not know what would happen if she invoked the ogham of the elder tree; she simply had a feeling the moment was right. The Muggle-Born Sanctuary was built on a Ley Line, so the power and the correct trees were there; the spell could be cast, so she went ahead and used it!
"Ruis!" Oleandra exclaimed.
"Have you gone completely mad!?" Mai screamed.
Ruis was a rune of death and endings, much like its sister rune Idho, the ogham of the yew tree, but unlike Idho's permanence in death, Ruis concerned itself more with the terminality of death; the end of all things…
And so, causality itself reversed.