Oleandra shot out of the crevice in the Map Chamber's floor like an arrow and landed, the Lethifold's black, leathery folds billowing around her in the nonexistent wind as she came to a halt before the four portraits of the Keepers. She saw that the female Keeper had returned from her trip to the Headmaster's Office; she and her colleagues were gathered within the grey-bearded Wizard's frame, discussing Oleandra's success in low voices.
"I say, standards have plummeted since my time as Headmistress," said Niamh, the only Witch among the four Keepers. "The Headmaster was curled up on the ground, and no matter how much I shouted, he would not listen to a word I said!"
Oleandra frowned.
According to her Reflection Doppelganger's memories, her clone had fed Professor Snape one of Oleandra's own Wideye Potions, which she had brewed to help her stay awake when she was studying for her final exams…
…in her third year at Hogwarts. She had missed finals in her sixth and fifth years, and she had been exempted from taking exams in her fourth year. No wonder Professor Snape was not waking up; the potion had probably gone bad years ago.
Now that she thought about it, she really ought to have Madam Pomfrey check in on him.
"Ah, excellent!" said the grey-bearded Wizard, spotting Oleandra at last. "Judging by the fact the school hasn't collapsed and that we're all still alive— relatively speaking, of course— I take it you've succeeded in mending the repository?"
Oleandra nodded.
"Since you've acquitted yourself quite well with the task we gave you, your nearly causing a cataclysm notwithstanding, allow me to introduce ourselves," he went on. "I am the de facto leader of our little club, Percival Rackham; to my left, wearing the turban, is my good friend Professor San Bakar, who taught the Beasts class of his living; to my right is Charles Rookwood, heir to the Rookwood family fortune and Professor of Transfiguration; and the charming Witch at my side is Professor Niamh Fitzgerald, who, as you might have already guessed, used to be Headmistress at this wonderful school."
Oleandra crossed her arms and shot them a withering glare.
"Does the name Isidora Morganach ring a bell?"
Shocked looks appeared on each of the four Keepers' painted faces. They exchanged dismayed glances, wordlessly trying to communicate with one another how they should approach this touchy subject. How could this strange girl, who hadn't even undergone a single one of their trials, possibly have heard that name?
"I see you've indeed heard of Professor Morganach," Oleandra said scathingly. "I'll spare you the trouble of figuring out how I learned about her. Her spirit was trapped inside the repository. She told me you murdered her in cold blood."
Great Fairies were terrifying existences, even when deprived of their true forms and forced into human bodies… but they were not invincible. Even at the height of her power, Morgan le Fay was defeated by Merlin the Enchanter at the end of their legendary duel, which lasted three entire days… and she was still remembered as the strongest Witch who had ever lived.
Despite their ability to learn directly from their predecessors, a Fairy's different incarnations were not the same people, no matter how much they resembled one another, or how skilled their previous selves had once been. Young and inexperienced Fairies could prove just as brash and hot-headed as human teenagers; like Oleandra, or Mai's previous incarnation, who had died at Grindelwald's hands when she had challenged him for the Elder Wand.
"Isidora was our most gifted disciple in the art of wielding ancient magic," said Percival Rackham sorrowfully. "We would never have—"
"My apologies, Percival," San Bakar interrupted him. "But as I am the one who killed her in the end, I believe I should be the one to tell Miss…?"
"Greengrass," Oleandra said shortly.
"…Miss Greengrass about Isidora," San Bakar went on. "As Percival said, she was extremely gifted, but she chose to make use of her talents in an extremely harmful manner. We tried to show her the extent of the damage she was causing, as her intentions were good, but she would not recognise the error of her ways. She forced our hands; had we not intervened, Hogwarts and its surrounding territories would have become devoid of life. She is the reason we began testing inheritors of lost magic."
Oleandra did not look convinced.
"Isidora constructed the repository below us, and many others besides," Rookwood explained. "She filled it with the emotions of the students and teachers who lived in the castle, and she irrevocably bound those emotions to the telluric knot the Four Founders built Hogwarts on top of… somehow. If you ask me, you must have met a fragment of her obsession, unwittingly drawn into the repository."
That much made sense to Oleandra. The Isidora she had met had seemed like a woman possessed.
"You see, Hogwarts now draws its magic from the repository, instead of taking it from the ley lines directly; it is why the castle seems so alive," explained Percival. "It is why the Grand Staircase's stairs seemingly decide at random to turn into slides, or arbitrarily change the floors they lead to, or why the suits of armour or the gargoyles sometimes leave their posts and go on walks. In our days, the castle's amenities were far more practical and far less whimsical."
At the beginning of the year, the new first-years were filled with wonder and curiosity, and their desire to explore in turn led the stairs to send everyone to the wrong floors. By the end of the year, the stairs became much more reasonable, but as finals approached, the students would grow increasingly restless, causing the castle's decorations to blow off steam in their own peculiar ways.
"Isidora robbed the students of their negative emotions," Niamh explained. "At first, this might seem to you like a good thing, but our magic and souls are inextricably bound to our emotions. Before long, those she had touched fell into irreversibly catatonic states… and still she refused to stop."
Ironically, despite many of Mai's incarnations being known as Dark Witches— which were far rarer than their male counterparts— they loved humanity more than any Great Fairy… in their own twisted ways.
"I understand," Oleandra sighed. "You had no choice."
Isidora's way of doing things indeed sounded a lot like Mai's.