When the time limit for the Dark Lord’s generous offer expired, there was no sign of Harry Potter or any of his little friends, not that Bellatrix honestly expected different, and so when the Dark Lord gave the signal, she joined the other Death Eaters and in a swirl of dark smoke, they all apparated to the Hogwarts Great Hall, immediately opening fire on anyone in sight, and the fighting began anew.
The battle quickly spread throughout the corridors of Hogwarts as the defenders retreated and the Death Eaters pushed their advantage. It was no doubt part of the so-called Light’s strategy, to separate them and lure them into traps, but when the Mudblood met her eyes for just a second in challenge and then ran down into the dungeons, no amount of logic could keep her from pursuing.
It was not difficult to follow the Mudblood down the corridors, though there were several attempts to ambush her. She treated them like the gnats they were, a quick dodge, a Bombarda at the doorway to block them in, until at last, in the lower levels of the dungeons and far from the battle, the girl turned to face her with a determined expression. Oh, there was fear in the girls’ eyes, delicious terror that sent thrills through her body and made her blood sing, and yet the girl faced her, pointed her wand, her wand, at her face and prepared to fight.
It felt like delicious irony, like fate, two witches facing each other with each other’s wands, prepared to dance to the death. Careful steps at first, probing spells easily shielded and avoided as they took each other's measure. Then more, faster, spells countered almost as fast as they could be cast, dodges where no counter existed or was not known. Quick shields causing their spells to ricochet, flashes of angry light making burn marks and holes in the walls that soon covered the corridor in flying debris.
The Mudblood was good, better than any eighteen year old had any right to be. But of course, she was better. Oh, the girls spells came out perfect, the intonation and wand movements exact and each curse flashed at her with deadly intent. But she was lacking in experience, her instincts were just a little off, a slight hesitation as she tried to decide which spell to use, her aim just a little off from where her opponents would be by the time the spell hit.
She would gladly admit it - she was soon toying with the girl. As the minutes ticked by and the girl only became more determined, her spells slowly becoming darker, Bellatrix was determined to push her to her very limits, to see what she was made of before she cut her down. Curse, shield, dodge, they danced, and she felt alive, her cackles ringing down the corridors unbidden.
As she sent another Crucio flying and barely dodged an organ-liquifying curse that sizzled by her ear with dark intent and made her blood sing with a twisted desire, she idly wondered which Black library the girl had dug it out of. Did the so-called Light know just how deeply their ‘golden girl’ had immersed herself in the Dark Arts? The girl could certainly give any of the Death Eaters a run for their money.. Oh, she had started out throwing stupefy’s and expelliarmus, as though not using her vast knowledge of the Arts somehow made her more Light, but it had been absurdly easy to bait her into answering fire with fire.
Stupefy’s had turned into blasting curses and cutting curses but soon blood boiling curses and darker, nastier spells were flying in both directions. It was a dance where a single misstep meant death, and it was absolutely exhilarating. She was almost disappointed it would be over soon, she was getting tired and the girl looked exhausted, her spells getting slower if no less powerful.
She was already moving to dodge when she heard the girls’ hissed ‘Avada Kedavra’, countering with an Assyrian bone breaking curse just as she stepped out of the way of the flash of green that lit up the corridor so intensely, she was startled to hear the scream as her own curse hit the Mudblood in the shoulder. Time seemed to stop as their eyes met, and then the girl's eyes rolled back in her head as she collapsed. The corridor was deadly silent after the hour-long duel, the only sound Bellatrix’s ragged breaths.
Her hand twitched and she stared at the unmoving form. Was she dead? She felt an odd disappointment at the thought, almost the pain of loss, but why? She was a Mudblood, one of them, filth good for nothing but death or slavery. But then... why wouldn't she? She had marked her, claimed her, she was hers. Bellatrix approached cautiously, but there was no reaction even when she bent to wrest her wand out of the girl's grip.
She cast a quick feather-light charm and bent to pick her up, uncaring of the blood that now stained her black robes. She felt a strange sense of relief when the girl groaned, and quickly reached up to touch her raven-skull necklace while balancing the now weightless girl against her body. “Portus”, she whispered, and tried to relax as the emergency portkey activated and yanked her away into darkness.
Then she was in Malfoy Manor, and she scrambled to put the dying girl on a couch while screaming, “Cissa! CISSA!”, likely sounding like a madwoman. Well. Nothing new there, her sister must surely be used to it by now. She quickly stood and turned as her sister entered the room, and merely pointed at the Mudblood, and said, “Save her.”
Narcissa stared at her for a minute, long enough she was starting to get impatient. She was about to open her mouth to demand, or scream, or screech, when her sister threw up her hands and knelt by the couch, “Fine! Merlin, what did you do to her?”
“Bone breaker curse, you know the one, makes the bone explode.”
“That explains all the blood,” her sister muttered, moving her wand over the girl in careful circles. “She’s hanging on with a thread, but I think I can save her.. get me some blood replenishers? And skele-gro, she’s going to need a new shoulder…”
Bellatrix tried to hide her relief as she nonchalantly went to the emergency cupboard the Malfoys kept in almost every room and grabbed the bottles in question, moving to hand them to her sister, “How long?”
“She should be awake in a day or so,” her sister snarled back while trying to force the potion down the girl’s throat.
“Excellent! I have to go help the Dark Lord clean up”, because surely the battle must be won by now, “oh, and Cissa? Don’t let her escape,” she hissed, then she twisted and apparated back to Hogwarts.