A/N: THIS IS THE LAST PART! NO MORE!

Kazui grew to be a fine young man with a strong moral compass, much to everyone's surprise, even his parents'. He had a knack for knowing when he was being lied to and ended up going into law, becoming one of the best and fairest prosecutors in a hundred miles.

(And if he used the abilities he inherited from his parents to find the evidence left behind to prove innocence or guilt, well – no one knew but him.)

Both Ichigo and Shiro were proud of their only child, even if the demon wasn't around nearly as often as he would have liked. (The hunters bitched about "back at full power" and "generating omens" and "upsetting the balance" and other things Shiro didn't pay attention to.)

(More importantly, he and Ichigo did eventually have sex again. The witch insisted on condoms.)

But time passed, as it always did and always would.

And Ichigo grew old.

It happened slowly, one wrinkle at a time, one orange hair bleeding into gray. His magic reserves never weakened, but his body stopped being able to keep up. His limbs lost their strength and tone, his hands started to shake. Eventually, he was unable to travel beyond Japan, then Karakura, then his own home. When that happened, he said his goodbyes to his son and surviving family and friends, then warded his room specifically to absorb the blowback and used Shiro's emergency summon.

The warding did its job, but even so he felt like he was caught in a typhoon for a second before everything settled again. Shiro's clawed hand smoothed over his hair.

"I'm ready to go. My body's falling apart around me, and it won't be too much longer before my mind follows. I want to go while I still know myself."

Shiro hummed. He didn't ask if he was sure. "Lie down."

The witch stretched out on his side of the bed, the demon standing next to him. Shiro flexed the fingers of one hand, claws briefly glowing red, before he dragged them through the air over his body, starting at his feet. He felt his body start to die as they passed, felt all his organs grind to a halt, and saw a glowing blue-white curl of mist emerge from his mouth, following the curl of the demon's claws before everything went white.

He was only vaguely aware of his family and friends giving their final goodbyes to his bare soul. Then Shiro :jumped:, and he felt briefly weightless ( although he didn't understand how he could feel weightless without a body that felt weight) –

And then they were in Hell. The witch had shape and form again, though he was still wrapped up in Shiro's energy. He turned to the demon, who said, "Come with me."

A ritual chamber awaited them, somewhere in the main fortress. Ichigo quickly lost track of the twists and turns, doors and halls; if he had to find his way back at a later date, he would never make it.

"Strip."

Ichigo did so, realizing in the process that he was young again, probably eighteen like when he modified his deal. Shiro was already nude when the witch finished and came to stand in front of him. The demon curled a hand around to cup the base of his skull. "I can't stop you from becoming a demon now that you're here," he said bluntly, "But if I force you to change, I'll be able to control it to a certain extent. You'll retain at least some of your Self and your humanity."

The witch considered for only a second. He was being offered a choice, but it wasn't really a choice at all, not to him. "Okay."

The demon pressed a hand to his breastbone and started feeding power into him. It felt even better now than when he was alive, but it burned, too, seared its way inside him and made him start panting at the heat. The demon stopped and pulled him close, but the warmth still smoldered inside of him.

And it was growing.

Shiro distracted him from the sensation by carefully pulling off his mask, then kissing him fiercely. Ichigo responded immediately, kissing back just as fiercely and moaning when the warmth rose higher. The demon laid him out on the smooth floor of the ritual chamber and stroked his hands down the human's sides, then pulled his thighs apart to settle between them. Ichigo hissed and arched as they ground together, then grabbed their cocks in one hand and started an easy rhythm that still made them both gasp.

The warmth was growing hotter, spreading further, starting to become painful. The witch hissed and started to fight against it, before Shiro distracted him again with another ravenous kiss. Ichigo bit back and writhed enticingly against the demon, who growled ferally. He snarled back, then started to fight, but Shiro's greater power won out.

The Change was spreading faster than he had anticipated, and though Ichigo was fighting it, he was also taking to the altered soul-state like a duck to water. "Quick and dirty it is, then," the demon murmured, and gave the witch only a perfunctory stretch before shoving in. The witch screamed and clutched at him, nails scrabbling for purchase on his smooth back, but he stayed hard.

The demon started to thrust – to rut, really; quick and dirty, like he said. Ichigo only demanded more, harder and faster and more pleasure. "I almost envy you," Shiro purred, forcing the witch to lie back and hiking one of his legs up over a shoulder, "Of all our Changes, this one is always the most… intense. I'd do it again in a heartbeat."

Ichigo arched under him with a gasping cry. The burn was changing – or perhaps it was just how he felt it. The pain was turning to spine-melting pleasure, compounding on top of Shiro's deep thrusts to make his mind go blank of everything except the bliss. More cries left him, but he didn't hear them. Just when he thought it couldn't possibly get any better, it did, and kept doing so.

And then it peaked, and snapped, fire and ice roaring through his veins, agony and ecstasy running rampant through his nerves. Shiro was right behind him, snarling as the soon-to-be demon tightened around him, but he pushed through the aftershocks to pin Ichigo to the floor of the ritual chamber as he started to thrash, the energy he had implanted now rushing freely through him.

Though it increased his power, he still wasn't quite up to matching the elder demon's strength; Shiro held him down as he writhed and Changed, white sludge bubbling up out of his mouth and spreading over his face to form his mask. It looked identical to Shiro's but with inverted colors, with more tattooed lines spreading down over his chest and shoulders. The lines made his skin look paler – no, wait, he was getting paler, his skin turning white. His nails grew into claws and scored the floor. Just when he seemed ready to start ripping himself apart – it ended, and he went still.

The elder demon held on a moment longer, then released him, though he remained where he was, still knotted with the other. The Change had caused some interesting sensations, but it was too soon for even a demon of his caliber to get hard again. His knot deflated eventually and he withdrew, but Ichigo remained unconscious – a sign that his human mind was successfully working to shield itself from the influence of his new demonic powers. Shiro remembered how he had been after his change; even with his prior experience, he had gone a little crazy under the influence before he learned to control them, instead of them controlling him.

Sometimes others never did.

After an hour, the elder demon got tired of sitting on the hard stone floor, and carried the newborn to his chambers and laid him out on the bed.

It took hours for him to wake. Shiro was researching something to use against a certain trio of traitorous hunters, who came to Hell to recruit an army, when he heard Ichigo's breathing change. He marked his page.

Ichigo sighed and stirred, peering around before noticing his new mask, complete with horns. "Gah! Shiro!"

The elder burst out laughing. He set his book aside, still chuckling, and turned to face the newborn, playfully jousting with their horns for a moment before answering the unspoken question. "I used my power to turn you. It's not surprising that you mimicked me in more ways than one. Although you've got a bit more color than I do." He tugged pointedly on one of the other's long orange locks.

"What the fuck!"

"And I'm glad to see that you've retained so much of your humanity," Shiro continued gleefully, "I would have hated for you to become boring like the others." He waved vaguely towards the lake of fire beyond his windows.

Ichigo quickly realized that the other was right. He still felt like himself, still cared about his family and friends, still wanted the best for their son – was still half in love with the demon who'd held his life and heart and soul in his hands, and not crushed him. But now there was an undercurrent of violence in him, a :lust-for-blood:, that called for him to protect his precious people by absolutely destroying their enemies, dragging them into Hell's deepest pits and putting the fear of God into them.

"How is this possible?"

"It's because of the way it happened."

Ichigo blinked. "The sex?"

"That's part of it." Shiro tightened the hand in the former witch's hair. "You were out of it, Ichi. Like, seriously out. All your defenses were down… so the power didn't have to break you, in order to Change you, like it usually does."

"If I had fought…?"

"Then when it finished, you'd have been a demon – in every sense of the word. Nothing left of you but your name."

"I'm glad that didn't happen."

"So am I."

"You're just saying that 'cause you want to fuck me again," Ichigo growled, but wrapped his legs around Shiro's hips anyway.

A/N: For the visual of what Ichigo's soul looks like, think "angel Grace" from Supernatural. Also, kudos to those who catch the teeny tiny reference to Skyrim!