With Cloud and Sora momentarily distract by Kairi's outcry, both silver-haired men attacked. Kadaj was fast, but so was Cloud, and he brought both of his blades up in ample time to block Kadaj's first swing. They spun around each other, steel flashing, a blur of black and silver. Kadaj spat taunts at Cloud—the traitorous elder brother, the failure, the coward too afraid of the unknown to embrace the power Jenova had once offered him. Cloud didn't dignify any of it with an answer; when once they would have stung him, perhaps enough to make him stumble, they meant nothing now. He'd faced his past, faced Sephiroth, and overcome them both. Jenova's poison had no hold over him anymore.
With the Heartless at his back Kadaj knew he couldn't lose, and to him this wasn't a battle but a game of pain. He wanted it to be humiliating, a punishment for Cloud's disobedience against Mother, just like she would have wanted it. Cloud killed Mother's favorite son, and he would pay. Kadaj drew first blood, nicking Cloud's cheek with the tip of his sword. The wound wasn't deep, but Kadaj knew it stung, and there would be more: many, many more.
-----
Sora didn't rise up to meet Riku's first attack but rolled aside, and his sword met nothing but air. Sora danced backward, trying to put some distance between them. In the next moment, Riku saw why. A white aura crackled around the outline of Sora's body as he called on the greatest power the Light had to offer him. Riku was almost blinded by its intensity and was forced to look away, throwing a dark miasma where he thought Sora had been standing to cover himself. The younger boy willed himself higher into the air to evade it easily, and Riku saw that his feet didn't even touch the ground when he dropped back down. "I said I didn't want to hurt you, Riku. But I will, if you don't give me any other choice," he said. With a flick of his wrist he sent both Keyblades that had been orbiting his body to strike hard at Riku. He deflected one, but the other hit, tearing at his leg. They came about again and again, almost too fast for him to avoid. He barely had time to throw off a fire spell at that blinding light, but his shot went wide and there weren't many more where it came from. The Riku-that-wasn't-Riku began, for the first time, to feel afraid.
-----
The Heartless were coming thick onto the platform now, the stream of black parting in the center around the two pairs of combatants to concentrate on breaking through the guards at the doors. The magically enhanced bullets the Shinra soldiers carried tore through the stuff of Heartless bodies, snuffing them out in an eyeblink. None wavered from their positions, even as one of their comrades, then another, then another was swept under the waves. At last Kairi found herself side to side with the dark-haired man, Tseng, the final member of the squad left her side. He had discarded his useless, empty handgun and was now facing the tide of Heartless with lethal grace using only his own limbs as his weapons. Kairi had never seen anything like it, but had no time to marvel. She realized he had purposely positioned himself between her and the rail, allowing her to use her magic freely. She continued firing off spells as fast as her lips would form them. Aerith did the same, obliterating Heartless with both magic and her expertly wielded quarterstaff, her gentle and yielding healer's nature gone taut as a steel cable against a threat to her homeworld and adoptive family.
Tseng was good, incredibly good, but against so many he didn't last long. A flailing Soldier launched itself with blinding speed at his side and gashed deep into his thigh with its claws. He cried out and fell to one knee. Two Shadows jumped on him and tore into his back, sensing the kill was near. Whoever he was, thought Kairi, he was willing to give his life to protect herself and Aerith, and that wasn't something that could be easily discarded. Aerith exchanged glances with her, and they both ran to him. Kairi stabbed both Shadows on his back through the head with her wand and Aerith knocked away another two away from around his legs. A lightning storm fountained up out of Kairi's hand, electrocuting everything within ten feet of them, but the black tide continued to boil over the railing. Tseng struggled up again, but it was plain that he could barely walk, much less fight. Aerith put herself in front of both of them, swinging her staff in wide circles at any Heartless that came near. Kairi's energy reserves were dwindling, and she wouldn't be able to protect them both for very long. "Hurry, Sora," she thought. "Please hurry,"
-----
In this form Sora was more than a match for Riku, even with the strength and speed Jenova had granted him, and they both knew it. Riku was bruised and bleeding, and his shallow well of magic sucked almost dry; for all that, he'd only managed to scratch Sora a handful of times. He knew that the boy was capable of much worse, but had restrained himself from striking a truly crippling blow. Whether it was out of love or stupidity, or both, he didn't know, but this hesitation was Sora's weakness. After all, he didn't have to win—he just had to keep on his feet until Sora's Light-born strength failed, or the Heartless took the door, neither of which would be long now.
Sora knew it too, and that he was almost out of time. He had hoped that Riku could find a way to shake free now that he and Kairi where there to help, but he couldn't wait any longer. A decision had to be made. Sora swallowed back his compassion, took hold of the whirling Keyblades and dove towards Riku. The teeth of one key caught in Riku's sword and wrenched it from his grasp, and the second Sora sent spinning at his other arm with enough force to shatter bones. The box fell from Riku's suddenly nerveless fingers, and before he could grab it with his uninjured hand, Sora called up a gust of wind that launched the box into the air high above their heads.
"KAIRI! NOW!" he yelled. She saw Riku's empty hands and the black speck in the air, and immediately understood. In unison they launched two almost white-hot fireballs, which instantly liquefied the heavy plastic and burnt the contents to ash. Riku reeled as if he had been physically struck and collapsed to his knees in front of Sora.
Kadaj screamed in agony. His control over the Heartless evaporated in that instant, and their ranks broke, unwilling to continue throwing themselves at prey with such lethal bites. Now…now there was nothing left to win for Mother except revenge. Kadaj, a dutiful son until the end, decided to take it on the one whose loss would wound his enemies' hearts the deepest. He charged screaming at Aerith and with one swing bisected the staff she raised to defend herself, flipped his double-bladed katana around again, and thrust it cleanly through her chest. "NO!" Cloud cried, and sprinted toward her. Kadaj drew out the blade and whirled to face him with bloodlust in his eyes, but before their swords met it was Riku who rose on unsteady legs and flung a dagger of dark energy at Kadaj that pierced his heart. He dropped where he stood.
Everyone on the roof capable of walking—Cloud, Kairi, Tseng, Sora, and Reno—converged to where Aerith had fallen. Cloud reached her first and dropped his swords to lift her and cradle against his chest, his expression slack with anguish. She was still alive, but her breath was coming in horrible, bubbling gasps. "Cloud, don't worry," she said, smiling faintly. "I can hear them so clearly. They've shown me how to touch it. You'll be safe now, all of you."
"Who? Touch what? Aerith!" he said desperately, but her eyes had already slid closed. The blood coursing from the wound bathed the white stone she wore on a thin chain around her neck, and as its pure white surface stained red, something happened. A few thin threads of light spun out of the center of the stone, followed quickly by even more, thicker tendrils. Cloud stared as they curled up his arms, making his skin tingle but not causing him any pain; they then shot outward to envelop the rest of people on the roof.
"What the…" Sora said, as two writhed around his legs and torso and even more flew through the air around him. "What are they doing?"
"Holy," said Tseng, leaning heavily against Kairi. "She called Holy. I didn't know..."
Five spears of light pierce Kadaj's motionless body, which seemed to evaporate into shimmering green mist that was quickly absorbed into the streams. They explored Riku as well, twining all around his unconscious form before withdrawing and moving on. Sora looked over the low rail to see them cascading over the sides of the tower like a waterfall, slicing through the Heartless clinging to the walls and dissolving them into nothing. Soon the roof was clear of the tendrils, which had spread out through the rest of the city seeking out any lingering Heartless and what was left of Jenova's sadistic family.
For all that this miraculous power seemed to be channeled through Aerith, it didn't heal her. She was completely limp in Cloud's arms and barely breathing. "Kairi, if we pool our reserves it might be enough to save her," Sora said, and Kairi nodded, tight-lipped and grim. They knelt down, one on either side, and took hold of each other's hands. Both bent their heads in concentration, pulling out every last particle of energy to pour into mending the wound. After several minutes they pulled away, both shaking with exhaustion.
"It wasn't enough," Sora whispered.
Kairi shook her head miserably. "I know," she said, hot tears slipping down her face, "but I don't have anything left."
"To hell with standing orders," Tseng said abruptly.
Reno gaped at him. "Sir?"
"Everyone, stay clear of the center of the roof. Reno, get the President's personal chopper from the south pad. We're airlifting her to the hospital in Sector 2. It was her blood that saved us all, and I will not stand by and let her die." Reno nodded his assent and took of running through the nearer door.
Sora rose to see to Riku, who was lying unmoving on the concrete. He swallowed hard as his eyes took in the damage the Keyblades had done and knelt beside his friend. "Riku?" he said hesitantly, shaking his shoulder. "Please wake up. Please be you." At first he didn't stir, but slowly his eyes opened as consciousness trickled like water into the dry beds Jenova had left behind when Aerith's magic had scoured its influence from his body. Sora was immensely relieved to see that his eyes had returned to a wholly unremarkable round-pupiled green. He was free.
"Sora…" Riku whispered, "thank you."
"You didn't think we were going to give up on you, did you?" Sora said, eyes shining.
Riku didn't answer as he tried to push himself upright with his uninjured arm.
Sora pulled him up the rest of the way and threw his arms around Riku's shoulders, burying his face in his silver hair. Oblivious to his own injuries, Riku let him. Eventually Sora released him and drew back. "Can you walk? We've gotta move."
"I'll try," he said. The world tilted crazily when he stood, but with Sora supporting him he managed to stagger to the outer railing. Reno soon returned with the helicopter, a matte black military model, and set it down on the roof. Tseng, limping heavily and weaving a little nevertheless took the copilot's chair, with the others filing in to the cargo area. Riku collapsed on the floor with Kairi and Sora on either side, and Cloud carried in Aerith. The short trip was completed in tense silence. Cloud kept his eyes locked on her face the entire time, as if he could keep her heart beating through sheer force of will.
A team of doctors was waiting on the roof with stretchers to take Aerith, and after a short argument, Tseng as well. Riku was pulled away to another room and his injuries tended to with brusque efficiency, then, unable to keep his eyes open any longer, he fell onto the narrow bed and slept.