So this was a shinigami's bankai.
He leapt out of the pillar, spraying wave upon wave of reiatsu out before him. She could see the edges of his outfit, which were now ragged and torn, and his attire was more form fitting.
But midway through the increase as he ascended...
His power changed.
It became dark and sinister and suddenly seemed to permeate the very air, saturating it with reaitsu, suffocating anyone who wasn't strong enough to withstand the prescence of such a malignant energy.
His energy was wild and rough now, constantly increasing, as if it had no limit.
Unperturbed as ever, Ulquoirra just stared up at the pillar with mild interest, hands in his pockets the hem of his robes flapping wildly about.
Through the light, Ichigo's face was suddenly revealed, as was the rest of him.
She could barely make him out from this distance, as he was now incrediby high up, practically touching the ceiling.
His giant zanpaktou now appeared to be smaller, and a long katana with a chain at its hilt....
Wait... what was that...
On his face?
As if her vision suddenly zoomed in...
She saw it.
His warm brown eyes were now yellow irises, and the whites of those eyes were now a pitch blac color. She could still see his orange hair, as the mask only covered his face and chin...
Still, she shivered as watery growl escaped him.
His left hand briefly rested on the flat of his blade, whilst the right held its hilt in a deathgrip.
Raising it up, he now seized its grip with both hands, twisting it around as he did so...
Dark red black light began to swirl about him, in a crescent like shape that spun, even as the power built.
She idly thought it looked as if a miniature typhoon was hovering in the air, just waiting to come down and wreak its carnage.
And down it came!
She had a second to get brace her feet from her cover, as with a scream Ichigo swung!
He came hurtling down, a bolt of black light, hell bent on Ulquiorra's death!
He moved with incredible speed!
One moment he was hovering in the air-
The next, he veritably slammed into the Espada, who somehow got a hand up to block the attack!
The earth quaked and she was nearly blown away in the resulting gale.
The black light thinned a bit to reveal Ichigo, who was straining against the lone appendage with all his considerable strength, cracking and shattering the hard floor beneath their feet, the pressure of his reaitsu disintegrating those shards mere moments later.
She found her own eyes narrowing, as Ulquiorra looked...
The ground, previously untouched where the arrancar stood, suddenly crumbed beneath his feet, in spiderweb cracks, then it just flat out crumbled.
Swinging hard, he somehow managed to use enough force to get Ulquiorra off the ground, and into the air, carried up by the red wave he flung!
Mild annoyance reflecting upon his visage, the silent arrancar swatted the blast away with his arm...
However, he had forgotten to take his momentum into account.
As a result of pushing off the blast, he collided with a pillar, the impact shattering it, as he passed through.
"GET BACK HERE!"
An enraged Ichigo suddenly appeared before him, and swung again batting Ulquiorra through another pillar, as he blocked the blade with his forearm again.
But Ulquiorra was far from done.
He went through about three more, backfirst, before he finally took action. As he approached the fourth pillar, he flipped himself in the air, and landed against the it feetfirst. Pushing off it, he left a small crater as he shot forward...
A crater which soon lengthened to turn the entire pillar to dust.
Time seemed to slow as she watched him speed back toward Ichigo, roundhousing the ryoka hard across the face...
Or rather, he would have, had Ichigo not Shunpoed back a step, landing on the ground.
Already he was building up for another swing, growling as he did so...
But as she watched, she could easily see that this one had more force behind it.
With agonizing slowness, he began to bring it back....
Black light again shown from his zanpaktou.
The entire floor crumbled when he spoke the name of his attack, and his eyes glinted with murderous intent!
What happened next was stunning, to say the least.
He swung, and a whip of crecent energy escaped his blade, tearing across the floor, hungry for blood!
Ulquoirra landed a second later, took a step back to brace himself, and raised one hand, clearly intending to deal with this attack as he had the others.
That turned out to be a mistake on his part.
The moment he caught it, he began sliding backward, despite his efforts to maintain his footing. In response, the wave buckled and bulged, growing larger with every second.
Strain began to show on his face as his slide picked up speed.
She watched his arm move a centimeter.
An inch now.
Further and further it was pushed back, until the attack was mere inches from his face!
The ground buckled beneath him, and his strained expression grew into a scowl. Finally, he brought out his other arm, which had still been in his other pocket, to deal with the cutting wave.
Briefly, he pushed it back to arms length, as both arms held the malevolent power at bay.
By now the wave was a large swathe of energy, that which nearly covered half the room, opposite her.
'Impossible!' Was Ulquiorra's basic train of thought, as his arms began to buckle, and the wave showed no signs of weakening, or stopping.
No... in fact, it seemed to be getting stronger!
"Go!" Ichigo all but howled, and the wave exploded into Ulquoirra, blanketing the room in stema and remnants of his dark power, gone just as soon as it came.
Immediately, she felt his power decrease dramatically.
She looked on in fascination, as the mask crumbled from his face, slowly but surely, falling to the floor and fading away.
She turned away from watching.
Ulquiorra was nowhere to be seen, and the fight seemed to be over.
She knew it was not.
In a matter of moments the room had been all but destroyed. The ryoka had been stronger than the Arrancar had believed him to be—but he was by no means invincible. As Ulquiorra had anticipated, his taunts had finally goaded the shinigami into action, and had made him reckless. His attacks were irritatingly powerful, but most were wild and inaccurate. If they hadn't been such wide swaths of energy, the shinigami would have missed the Espada on numerous occasions.
It was time to end this—it wouldn't be wise to leave Orihime alone for any extended period of time. He knew better than anyone else that the inhabitants of the castle were not happy about her presence there. It was his, Ulquiorra's, nearly constant presence that kept the others at bay.
Without his mask, the ryoka could obviously tell that his attacks weren't having any effect.
He leaped for an opening in the wall, perhaps in a mad attempt at escape with his allies, or perhaps only to rest for a moment or so. But Ulquiorra wasn't one to allow him that luxury. Time was of the essence.
He appeared in a blur beside the shinigami, whose astonished gaze met his in an instant, and then moved down to observe the orb of viridian Cero the Espada held in his palm; just before Ulquiorra released it at point-blank range.
And it hurt.
The shinigami flew back, crashing into an opposing tower far away. The Espada was there in an instant, just as the ryoka was pulling himself forcefully from the debris. Then, oddly enough, the shinigami began to laugh quietly. Ulquiorra felt an uncomfortable sensation over the tattoo just underneath his torn surcoat. The tip of the sleek black blade was pressed against his chest, though it trembled with the shinigami's effort to keep it placed there.
The ryoka looked up, his face fearless and arrogant.
"I guess you've got to be Aizen's most powerful, huh?" he asked, grinning. "So if I just take you out right now, it'll be a major blow to his little army, won't it?" Ulquiorra blinked once, his pale hand taking the slim edge of the obsidian sword and pushing it aside. The coat tore with its passage, revealing the ebony number four emblazoned in the Espada's stark white skin. His green eyes gleamed with satisfaction at the look of fading hope on the ryoka's battered countenance.
"Even if you were to somehow get past me, shinigami," Ulquiorra began quietly, "there are three others more powerful than myself lurking these halls." The Espada felt the Soul Reaper's tight grip begin to loosen at the hilt of his sword, but Ulquiorra held it steady at its tip. "But you do not have the capacity to best me, so it makes little difference."
Ulquiorra's other hand tautened, his fingers forming a deadly sharp point.
The Espada struck; he all but grimaced to see the wounded shinigami faint in front of him while he withdrew. But the ryoka was alive all the same—it had been a calculated miss. Ulquiorra blinked down at his fallen foe, deciding that he was a complete fool, and that he would probably regret the decision later.
Yet he knew it didn't matter.
The alternative was unacceptable.
Ichigo did not faint.
He was concious as Ulquiorra walked away, footfalls echoing in on themselves.
His face twisted into a scowl, but he could not make his body move.
He lay there for awhile, until at last, he could move again, and even then, only his arms, as zangetsu returned to normal.
He looked to the right, and saw that Nel was perfectly fine.
She looked to be very upset though.
"I couldn' do anythin..." She lipsed, and clearly looked like she was about to burst into tears.
"I'm fine... He mumbled, trying to rise, edging forward on his arms.
Though it hurt like hell, and though he left a trail of blood in his wake, he managed to pat her on the head, then somehow not cry out, as she hugged him, and started sobbing into his chest.
"See? (cough) Just f-fine." He stammered.
"I-Itsygo...Sobbed the girl.
He tried to get up again.
Until a shadow fell over him.
A solitary figure looked down at him.
Green eyes gazed calmly out at him, and rough, spiky blond hair cascaded down her back.
She was clad in an oddly-cut variation of a whitejacket that has long sleeves and bares most of her midriff.
The lower part of her jacket is slightly extended to cover the latter.
She also carried a blade on her back; the sword itself was notably broad compared to others and has a western-style guard, and white hip hugger slacks finished off the outfit.
The remnants of a strange white mask were partially covered by her collar, but it is clear that she at least has pieces of mask on both sides of her cheeks as well as thinner fragments that frame her eyes.
It took all he had not to stare at her.
When he did not speak, she did, bluntly.
"What now, shinigami? What will you do?"
He tried to rise.
"If you're here to kill me arrancar, I ain't going down without a-
She raised a finger to silence him.
"I am not here to kill you, Kurosaki Ichigo."
"Y-You know me?"
She reached down, and roughly pulled him up, along with Nel.
"Quite a bit actually."
He did a double take.
She pulled a small capsule from one of her nonexistent pockets.
"We'll talk later. Right now I need to get you patched up, and I can't it you don't-
"Not that, I mean, why the hell're you helping me?!"
She paused for a moment.
"It has become rather boring around her of late."
He swallowed the pill with great reluctance, then gasped as his wounds all healed.
"You interest me." She stated simply, now moving to head outside.
"You want to rescue the woman, don't you?"
In a rare moment of exasperation, she rolled her eyes.
"Honestly, I do not intent you or your companion any harm. And my word is my bond."
He frowned, following her.
"What's in it for you?"
She looked over her shoulder.
"As I said, curiosity. I need something to do, and you seem to be a topic of great interest to all of Soul Society by this point."
They rounded a corner, and in there path was a nondescript arrancar.
"H-Halibel-sama! What're you-
She disintegrated him with a quick cero.
"As you can see Kurosaki, that is my name. I expect you to address me as such."
Ichigo managed a dumb nod, as he kept pace with her.
"So you're on my side then?"
Through a door, up a set of stairs...
She paused to give him a look.
"No, I am on no one's side but my own."
Then they continued into the bowels of Las Noches...
And through another door.
Ran smack into Ulquiorra.
Halibel stopped immediately.
Ulquiorra looked to be quite surprised, but only for a moment, then he saw Ichigo, and put two and two together.
Then his blade was drawn.
The steel of Halibel's zanpaktou met his seconds later.
"I see, so you are a traitor after all."
"I was never on your side to begin with," she replied, leveling her right hand at him, as it now danced with sapphron light.
"Gran Reina Cero."