Ryuk had never been on Kira's side or L's. He'd made that perfectly clear on several occasions.

But Ryuk was on Light's side. He couldn't help it, really – he was the best thing that had ever happened to Ryuk, the best person who could have picked up his Death Note, and Ryuk was as hopelessly fascinated with him as the poor detective Light killed with a smile. They called him a human's pet in the Shinigami Realm, but Ryuk defied any one of them to spend a week with Light and not be sucked in.

He didn't stay close to Light because of the rules. He could leave at any time. He'd scout out places for Light (for apples) check if there were cameras or people or interesting things. When Light slept, Ryuk would slip through walls and wander the streets looking for those humans awake and out at that time of night, searching ceaselessly as ever for entertainment. But when Light woke it was to Ryuk's face hovering above his, wings spread like a hideous canopy, as if he'd never left at all.

Light was interesting. It was that simple.

Ryuk would spend every minute at Light's shoulder, watching him eating lunch, being bored in class, talking with – hah – friends and at the end of the day even he would begin to doubt that Light was Kira. That was interesting – to see how completely and utterly he could hide within himself. But with the Death Note in his hands, that was when things really got exciting. Kira, and the use to which he put the Death Note to, was wonderful. He'd write names in the Death Note with his left hand and he'd solve homework equations with his right. He plotted murders with a smile, destroyed lives with a laugh, and then slept deeply and dreamlessly. He teased at the problems L and his successors and the police threw at him, unravelled them, studied every facet of their innards and then put them back together again, so precisely and subtly different that nobody but him would ever untangle them again. He calculated every action and every probable reaction – and then he considered the responses he could give for every single one of those reactions.

A never-ending basket of apples within reaching distance and Ryuk would be happy to do nothing but watch Light forever.

Ryuk said he wasn't Kira's side, and if he wasn't on Kira's he certainly couldn't be on L's, but Light knew every problem and potential threat and Ryuk knew Light – it didn't matter that Ryuk wasn't on his side. If it were necessary, Light would find a way to make him tip the balance to Kira.

He'd enjoyed seeing Kira surface when he refused Light something, and even more than that he'd enjoyed seeing what Kira would come up with to sidestep his rejection, automatically adapting his strategies around Ryuk's whims. It made Ryuk feel ridiculously important that Light should be forced to alter his careful, exacting plans because of him. (The detectives didn't count – Light had not only taken stock of their defences and responses, he'd assimilated them). He would let Light bribe him with apples and vague promises of interesting things; he played games with Light and knew Light was at the same time playing far subtler, more complex games with him.

He remembered Rem, puzzled and incredulous, hating Light and demanding to know what he saw in the boy, why he didn't kill him, the arrogant human, treating him like a particularly dim pet. It made Ryuk laugh. Poor Rem, masterfully outmanoeuvred and destroyed with her own love. Ryuk liked to think that in the moment of her death, realising how skilfully Light had backed her into a corner, into destroying herself for him, she understood what it was that made Light glow among humans.

(kira, he had said one night to the sleeping Light, meant something entirely different in the Shinigami tongue, something deeper and darker without a proper equivalent among any of the human languages. The closest thing he'd heard, he supposed, was 'god killer'.

Ryuk thought it suited him, this human who was more of a death god than any Shinigami. Light would kill him one day, just like Rem and Shidoh, because sooner or later his need for Light to live and play his far-reaching games would outweigh his desire to stay alive and find other, different interesting things.)

For Light and apples Ryuk was willing to do pretty much anything.

But. He wasn't on Kira's side. And it wasn't Light that begged him for help.

So when the time came, he wrote Light's name with every appearance of amusement and dismissal.

The human who uses this Note can go to neither Heaven nor Hell. But Light knew all the rules and all the ways around them, and Ryuk had watched Light for so long, he had to have learned something. Not enough to be satisfied, not enough to be able to find things interesting that weren't in some way connected to Light and his brilliant and convoluted mind, but enough.

There were thousands of reasons Ryuk could give for his refusal to allow the proper things to take their course, but the only one he was willing to confess to was that he refused to be bored. And life without Light was boring.

Before he met the human known as Yagami Light, Ryuk might have been satisfied with the immense variety of humans scuttling around, living day to day and making the most of their pathetically brief lives.

Humans were fun, humans were hilarious, but-

After Light nothing was the same in either the human or the Shinigami world and sometimes Ryuk wondered if he ruined Light or if Light ruined him. Then he shrugged and decided that it didn't matter which one of them had altered the other because he'd liked watching Light and Light had enjoyed sharing the inner workings of his beautiful intricate plots and traps with Ryuk. So many of Kira's best, most cunning and ruthless mini-games began with the announcement 'You might find this interesting, Ryuk.'

Ryuk inevitably did.

They fed off each other's attention, he supposed. (Maybe Light felt that honour went to L, but Ryuk was there first. So… hyuk hyuk.)

Light was one in a million, a billion, something unique that would never occur again, L had known that – and so did Ryuk, and better.

He'd played with humans before, he'd watched other shinigami try since and none of them had come even slightly close.

It wasn't that he felt he owed Light something – ridiculous, because if he and Ryuk shared anything other than a desire to avoid boredom, it was a certain disregard for human life; nothing would have changed that, Death Note or no Death Note, Ryuk thought. He didn't believe his presence had brought Light misfortune – Light said himself that he'd been bored out of his mind, that the Death Note falling into his hands was the luckiest thing that had ever happened, was destiny. Light had made his own luck with it and was his own downfall.

No, he owed Light nothing. It was simply a matter of… interest.

That was how he pitched the idea to the Shinigami King, anyway.

The others could make all the pitying and derogatory remarks they liked about the decline of greatness (as if any of them were ever great in the first place, doing nothing but gamble, forgetting to even write names) and one of their kind being reduced to little more than a pet, but none of them could say they hadn't been entertained.

So Ryuk had made a deal out of Yagami Light for Yagami Light.

A second chance, a chance do things over, on the condition that he saved as many lives as he'd taken.

Time has innumerable dimensions moving concurrently, like the warp and weft of cloth, and history unfolds in countless ways – to take the single bright ribbon that was Kira, the thread cut short, and turn it back on itself was a small matter with the Shinigami King's blessing. A human whose name is written in the Death Note may not be brought back to life. But if that human hadn't been born yet, it wasn't, technically speaking, bringing them back to life, was it?

Besides, the thought of sharp-tongued maze-minded Light trapped in a wriggly little pink baby body was enough to send Ryuk into full-blown convulsions of laughter.

The mess it was going to make of the human world was just a bonus.

It was win-win as far as the King was concerned. If Light lost, the kingdom gained a very interesting new death god. If he won, there would still have been years of entertainment watching him work his way across the board in the meantime. The likelihood of the human winning was infinitesimal.

Ryuk's ever-present grin had only widened at the misjudgement before he went off to recover his human.

"Impossible, Ryuk." Ragged and exhausted, so recently reconstructed the memory of bullet holes still bled sluggishly, and Light still had the arrogance to tilt his head back with an irritated scowl and speak to Ryuk, to the Shinigami that had killed him, as if he were an idiot. Ryuk would have been disappointed with anything less.

"Oh? Kira has finally found a task impossible for him?"

"…you've taken your lessons about human nature to heart, haven't you, Ryuk?" Kira's eyes were redder than the skins of the many, many apples Light had given him over the years. Fascinating, how the truth of him was visible at last. He liked those eyes much better than the time they had been wide and brown and blind to him. That Light was nice, in his soft, human way, but Ryuk had never been so impatient in his long, long existence as when he waited for Light's plan to fall into place, for him to get his memory back and start entertaining Ryuk once more.

That, and it had irritated Ryuk no end to realise that were still aspects of Light/Kira that were unknown to him.

By the time Ryuk had arrived in the human world, five human days after dropping his notebook, Kira was already waiting for him. Ryuk had watched him as he slowly remade himself further in a shinigami's image, watched him become colder, more cunning and ruthless and detached, watched as he gained sharp edges, became beautiful the way a finely crafted sword or a forest fire or a tiger was beautiful. Kira would kill his family if he had to, Kira would kill anybody if he felt he had to. Ryuk sometimes closed his eyes and listened to the scratching of pen on paper, to the low chuckles, and sometimes he opened his eyes expecting to see another shinigami (albeit one more conscientious of his duty as a death god) in front of him. Light would be furious at the presumption; Ryuk considered it the highest compliment he could give.

In the night, sleeping, Kira would melt away from Light's face like a bad dream and there would be nothing but an ordinary sleeping human in front of him. Ryuk once phased his hand through Light's ribs to tickle his heart and startle him into furious, hissing wakefulness. He never repeated the act after Light gave him a thorough and comprehensive lecture on the human body and its fragilities. After that he restricted himself to kicking him when he was truly desperate for attention.

On the cusp of sleep, Light was so different to Kira he'd thought that he'd known every part of the human there was.

But Light, blind to him, oblivious to the side of himself the Notebook revealed, that Light was… soft. Ryuk had watched him constantly at the viewing pools, as constantly as he'd watched him when Light had been his human, and Light-without-Kira was… soft. There was no other word for it. He was never boring, as Ryuk had discovered during their separation that other humans could be. But he was different, and he wasn't Ryuk's.

Ryuk had actually managed a pout when he'd seen how very different Light was while chained to the detective, and cursed the fact that with his Note buried he was no longer permitted to haunt the human world. He would have given his eyes freely to see the change up close.

"So?" he said curiously.

"Even appealing to my pride isn't going to help here," There was a first time for everything, Ryuk supposed. "Do you have any idea how many I killed as Kira?"

"Uhh. About a fifty a week…?" he hazarded, mouth twisting for a moment out of his permanent garish smile as he struggled to remember. There had been so many names, so many faces, and Light might be able to remember them all, but Ryuk had been interested the deadly games that resulted. The numbers had never been really important except for the sheer quantity of them surpassing anything Ryuk had ever seen before.

"A good, if very, very conservative estimate. We'll begin there, why not. Six years makes that…" he raised an eyebrow expectantly.

What was he, a calculator? Light was supposed to be the genius in this partnership. …Human terms, human months and weeks and days… that meant… "…fifteen thousand?"

"Nice try. Ryuk, one of the best estimates someone has made for the number of people I've killed over the last six years is over two hundred thousand. Now do you see my problem? I'm good, Ryuk, but even I'm not that good. It's much easier to take a life by writing a name down than it is to save one."

Ryuk considered pointing out that Light had been dead longer than he believed and his last six years weren't the same as Ryuk's, then decided it was probably distracting and beside the point.

Light had talked to him about the Death Note and how he felt it cheapened human life once, early on, before he started forgetting the lives he took meant anything other than another game with L. He'd sat next to the window and told Ryuk it was ridiculous, how easy it was to kill, nothing more than a few scribbled characters and a picture in his mind. His hands were so clean it wasn't even funny, he'd said. Ryuk had watched his eyes above the momentary expression of discontent and had known Light was thinking that the only suffering all his killing would bring him would occur after his death, when he was reduced to nothing and wouldn't even know he was being punished. Ryuk, and Light's decision to pick up a black notebook, had meant that everything Light could ever do would have to be done before his death.

Ryuk tried to turn his head upside down while still attached to his neck. "But Light, surely you don't want to stay here?"

Light gave him a withering glare. Ryuk had seen him die, and he was still capable of making him fear for his life. A Death God. Fear for his life. Now that was impressive. "…of all the Shinigami out there I had to get you." He muttered irritably. Ryuk tried to be insulted, but was far too used to Light to take offence. "No, Ryuk, I do not want to stay here. But the task is impossible, surely you see that."

Ryuk scratched at one wing reflexively, remembering Light's rants about L, Kira, humanity, L, godhood, criminals, morals, worship, L, optimism, right, wrong, L… "That's what L said about Kira's idea to change the world."

"…you really have gotten good."

Ryuk decided there might be something to the 'pet' jokes after all, that he felt pleased at a statement that was – in Light's inimitable way – both insulting and as complimentary as it got. "Games, Light. And apples. Apples."

Light smiled. It was the first time Light had ever smiled at him without the sharp judgement of Kira behind it. Oddly, he thought of the detective, and how many of those smiles he had seen and not appreciated. Kira was fascinating, Kira was everything Ryuk could have hoped for when he dropped his Note... but sometimes he wanted Light, levelheaded human Light, wanted to see, to hear, to know the difference, wanted the chance the detective got and scorned for the sake of solving his case as 'Yagami Light is Kira'. Ryuk had wanted so desperately to see Kira-less Light up close, and Light's precious sanity anchor couldn't care less. He suspected there might be some of the poison humans called irony in there somewhere.

"You're doing this for yourself, you bastard." Light said, low and loving, speaking to an old, old friend, and Ryuk had to resist the urge to look and make sure they weren't, in fact, standing at L's grave or something.

"You wouldn't trust me if I weren't."

"Heh. When do I leave?"