Disclaimer: As usual, I own nothing literary wise and am just grateful to the original authors for creating such brilliant characters that can inspire people like me to want to read/write more about them. Thanks!

A/N: Let's just say that things are never the same when Harry Potter is involved, and that he solves as many problems as he creates. Sound like fun? I thought so. Harry had grown differently in my universe, and he's become rather cynical I suppose. Give him an alias, send him to Japan, stick him slap bang in the middle of the Kira case, add the world's best detective, the world's worst secret, and what do you get?

This.

Chapter 1

Harry Potter was 23 years old, and he pretty much had it made. He was a cracking Auror, with people constantly saying things like, "A credit to the department you are, Mr Potter!" and, "No idea where we'd be without you Mr Potter!" and even "You should be our Minister of Magic Mr Potter!" but truthfully it all meant very little to him now in his office as Head of Department, minutes before his departure half way round the world, probably to get killed by some nutter with a god complex.

Harry had pretty much revolutionised the way the Aurors worked in his four years as Department Head, and he was amazed the department had survived as long as it had.

Basically he had started Auror training fresh out of Hogwarts, expecting more than what he got. He finished the three year training course in just under a year, and was the youngest to complete the training in history, not that anyone expected anything different. Harry figured he should be happy, and that it was a brilliant achievement considering that he wasn't actually that bright. The problem was that he just wasn't satisfied in the slightest. He got the job as an Auror, and yet again, spectacular things were expected from him. His Team Leader and others actually looked to him for advice, and if there was ever a problem, it was, "Oh I know! I bet Potter will know exactly how to deal with this!"

Soon Harry found himself in the middle of a department full of disorganised, inexperienced rookies, mostly anyone of any standing having been killed in one of the battles with Voldemort and the last of his Death Eaters. Most of the muggleborns that were left had struggled in the muggle world before returning to wizarding society after the ministry had been cleaned up. Kingsley was the Department Head at the time, and was pretty vocal about not wanting the job. Being head of the department meant that Kingsley not only had longer hours with ten times the paperwork, but he barely left the building due to the number of Death Eater trials, and it was fieldwork that the man excelled in. It wasn't long before Harry found himself in Kingsley's office, being offered the job of Department Head.

It didn't take Harry very long as an Auror to mentally catalogue every single flaw and it didn't take long after that before he was thoroughly disgusted by what the Aurors didn't know.

Let us just say that a Dark Wizard escaped to the muggle world. The ignorant Aurors were more likely to cause a scene than the criminal. More time and resources were wasted cleaning up after the clumsy Aurors! It was like the 'Obliviate' charm meant that stealth was a thing of the past. muggles were treated more like an ignorant herd of cattle when it came to these things, and the witches and wizards had been removed from them for so long that the users of magic had fallen into an age old trap.

For so many years, advances in muggle technology were so few and insignificant that the Wizards took little notice, and they became complacent, so used to thinking that the muggles weren't a threat anymore since they'd packed away their stakes, pitchforks and flaming torches. Yes, the general magical population had noticed the bigger, shinier buildings. They'd noticed the cars on the roads, and the planes in the sky as they'd passed them on their brooms, and they'd laughed at them, thinking along the lines of, "Look at the cute little muggles! Trying to copy magic!"

Well, that was until some poor unfortunate soul had gotten a bit too close.

That had been one hell of a mess to clean up (way before his time thankfully). From there planes were generally avoided by broom travellers. Still though, wizards had noticed these advances and yet pure-blood culture meant that very few truly understood what it all meant. If anything the muggles had more tricks up their sleeves than the wizards in general knew about, and that ignorance could cost them dearly. Muggles weren't inferior in the slightest and if the wizards didn't keep up, then there would be no secrecy between their worlds.

At eighteen years old, with the Death Eaters practically non-existent, and the wizarding world being peaceful again after so long, Harry had noted that the main problem was laziness and ignorance. Witches and wizards were positively medieval. Compared to the muggle world, the wizarding world was stagnant, and not only was there nothing being done about it, but the Aurors were the ones being run ragged trying to hide their existence, and the Aurors didn't have a clue about the muggle world.

Training consisted of Advanced Apparition (wards, tracking, and masking), Combat Spellcasting (dodging, offensive and defensive), Portkeys (basically, only Team Leaders are allowed to make them in dire emergencies, and if you need to track a portkey, call in the Portkey Regulators. If you need a portkey, apply for one to the Portkey Regulators. They stretch that into a course that normally lasts three months), Stealth and Disguise (detection, neutralising, spellcasting), Strategy (raids, arrests and the like), Dark Magic (detection, neutralising etc), and a very small section on muggles.

Basically, "If muggles get involved, call in the Obliviators, and keep them busy until they get there. Now, to call in the Obliviation Squad..." That was it. This led to Aurors blundering their way through muggle society and calling the Obliviation squad to clean up, which they did a mediocre job of.

Harry had reluctantly agreed to accept the job on two conditions. Kingsley had raised his eyebrows at his conditions, and had asked if he'd like to be admitted into St Mungo's.

He'd replied that no actually, he was being serious and would like it arranged for him to have the necessary paperwork for six months of muggle military training, with the aim of hopefully improving Auror training in the future. Also he was serious about wanting to live for six more months as a muggle, either training or otherwise. He'd said that muggles were more advanced than they thought, and had security cameras in many streets, and that if there were no wizards that understood how they worked then eventually something would be caught on their cameras and their secrecy laws would be for nothing. It could cause chaos. He'd brought up the internet, and how muggles had inventions that put the wizarding world to shame, and that like it or not, if wizards didn't move with the times, they would be discovered. If something did happen to be caught on their cameras then there was nobody in their world who knew how to sort a mess like that out. There was nobody even checking for events such as muggle security tapes recording something they shouldn't. Also as Head of the Auror Department he should gain the experience of surviving amongst muggles.

At least if he did this then he'd be able to train the Aurors in stealth among the muggles, which was at an all time low.

He hadn't mentioned the tiny issue of having split up with Ginny recently, and Kingsley had either put it out of his mind or tactfully didn't bring it up. Either way, Harry was thankful.

Arthur Weasley had amazingly enough become Minister Weasley, and had supported Harry wholeheartedly. He had even gone as far as speaking to the muggle Prime Minister who, in his eagerness to show the wizards the best they had to offer, had agreed on specialised training for Harry. Agreed of course, with the condition that Harry be under magical oath never to reveal his training unless authorised to do so by the current Prime Minister, unless it was a life or death situation, either his own life or someone else's, magical or muggle. There wasn't much choice other than to complete the oath, even if Harry thought that all this fuss was unnecessary, after all, both the Minister of Magic and the muggle Prime Minister were involved, so he couldn't exactly say no.

So that's what Harry had done, and at 19 he had returned to the Auror department fitter, happier, and faster than ever before, and had become the youngest Department Head ever.

From there Harry had completely overhauled the training grounds, writing his own training program, which had terrified the newly termed Auror Cadets into almost wetting themselves. After seeing the benefits on Harry, they'd soon agreed that they should update the program. He'd wasted no time in enlisting Ron and Hermione's help to design a mammoth obstacle course including a non-magical area reminiscent of the muggle course where he'd almost passed out on numerous occasions before his muscles had gotten used to the constant exercise.

Ron had taken up his friends' challenge with gusto, saying that there's no way Harry could go through it and he couldn't, and had just completed his muggle Auror training, and Hermione had spent the time on her latest project, which was trying to create a room of requirement for the Auror training grounds. She was already famous in her own right not only for her actions regarding the final defeat of Voldemort, but for creating the first ever magical battery for powering muggle devices in magical surroundings, which she'd then modified into generator-like devices called Magisockets that were disguised as plug sockets that you could stick on any wall. It powered anything with a plug. Mr Weasley was ecstatic and had gone mad in the Burrow, much to Mrs Weasley's dismay. It had taken off amongst the muggleborn and half-blood population, and George Weasley was happy to stock them in WWW.

Arthur Weasley, who had protested at first after being offered the job, had soon found himself enjoying cleaning up the Ministry, employing many of the returning muggleborns into positions vacated by those convicted of Death Eater activity. These days the ministry was running smoothly, and due to Hermione's Magisockets and very little convincing on her and Harry's parts, Minister Weasley had decided to open a Technology department in the ministry, focussed on muggle technology and what it was capable of, and how to avoid potential disasters. He'd taken Harry's advice and soon volunteers were in the muggle world learning about computers.

Nobody had any arguments left when it was mentioned that it would be rather stupid for them to be blown to smithereens by some muggle nuclear warhead in a random muggle war they knew nothing about. It was telling when a majority of the protesters then had to be told what a nuclear warhead was, and after that they were more willing for there to be a department to keep up with whatever the muggles would dream up next, as long as it wasn't them, their snobby children, or anyone related to them doing the work.

The problem now was that Harry had been working almost constantly for months now, and he desperately wanted some time off, but he had to travel to Japan where the technology department had found a potential disaster. The department had been in shock as they had watched a recording of Lind L Tailor dying live on national television, and then as a large gothic 'L' was displayed, and the evidence revealed. Not even wizards could kill from a distance with just a name and a face.

Minister Weasley had been called in straight away, who had immediately called Harry. Next thing he knows, it's been decided that as the person most experienced with muggles and blending in successfully, he'd be the one going to Japan on boxing day to find out more about this mysterious 'Kira'. He'd be leaving for an indefinite period of time whilst Ron and George took care of things at the office, George having hired Lee Jordan to take care of WWW before he'd joined Ron in Auror training. Together, and with Minister Weasley's help, they had ironed out a few details with the Japanese Ministry and Harry would be going undercover disguised as an officer in the NPA, in the department aimed towards catching Kira. This would be the best way to find out what was known so far, and to keep up with the case since they couldn't rely on the media for accurate up to date information. Harry would do his own investigating on any leads using magical means during his spare time.

Harry sighed, looking around to make sure he wouldn't forget anything, and headed towards the International Floo. He'd already said his goodbye's, and would be heading directly to Japan, and from there he'd apparate to a flat that had already had the rent paid in advance for the next six months.

Before long he was standing in the floo queue (hahaha!), and a rather large flashing sign caught his attention.

DON'T FORGET YOUR TRANSLATION CHARMS!

KEEP YOUR ELBOWS IN WITH YOUR BAGGAGE AT ALL TIMES!

ALL ANIMALS MUST BE CHECKED IN CAGES!

Harry snorted at the poor wording and shuffled forwards, encountering another sign on the opposite side.

YOU'RE ALMOST THERE!

APPROXIMATE WAIT: 3 MINUTES

HAVE A NICE DAY!

Harry sighed and looked to the wall where there were clocks displaying the time of any country you could imagine, in alphabetical order. He noted that it would be roughly 6:30pm when he arrived to his flat if the apparition point was nearby, which it should be.

He could have just apparated the whole way but he was already rather tired out after a restless night. Even after all these years he still put up silencing charms before he went to sleep. Months of nothing but work and sleep with very little real food in between had taken their toll, and apparating that sort of distance now left him rather tired and short tempered for a while. Not advisable when he was supposed to be going to the NPA building at 7pm.

As far as anyone there would know, his name was Kinjo Ryuuki, transferred from Okinawa after taking an interest in the Kira case. A loose paper trail had been created, in case anyone looked a bit deeper, but truthfully Harry hoped they didn't, as he didn't fancy having to explain himself if someone caught on to the fact that Kinjo Ryuuki didn't actually exist.

Soon it was his turn, and with one last look at Britain, he dumped the floo powder and said, "Japan International!"

He spun through the network, glad he hadn't eaten anything that morning, elbows tucked firmly into his sides as the sign suggested, hoping that the torture would be over soon and that he wouldn't fall flat on his face in spectacular fashion when he was spat out in Japan.

Unfortunately fate decided to have fun and Harry came barrelling out of the fireplace headfirst and was forced into a combat roll more commonly utilised when trying to avoid getting shot in the ass. He cleared the soot with a wave of his wand and raised his head to see the entire room frozen in place and gawping at him. He quickly gave a half shrug and a sheepish smile, and dodged out of there as fast as he could, before stopping further down the corridor to perform a translating charm on his glasses so that he could read the signs telling him where to apparate from.

Before long, he'd found where he needed to go and apparated to the flat that had been set up for him. It was one of many muggle apartments in a rather high tower, and Harry whistled in appreciation as he saw the view from the floor to ceiling windows leading out to his own private balcony. The sun was low in the sky and the view of the Tokyo skyline was beautiful. It was a shame that he probably wouldn't be spending very much time here.

Mindful of the time, and that he only had 10 minutes to get ready if he wanted to avoid being late, he quickly dumped his miniature trunk onto the bed. Waving his wand, he transfigured his wizarding robes into a sharp muggle suit, and made his way into the bathroom.

Standing in front of the mirror he contemplated his face. If this Kira needed a name and a face, he wouldn't be getting either. He needed to change his facial structure so that nobody knew what he looked like. Generally these transfigurations could last up to ten days; Harry's were more like 15 or 16 days, but he would be reapplying it every week or so to be sure. He carefully made his eyes look slightly more Japanese, and made his nose slightly smaller. Grimacing slightly at his reflection, he decided to make his jaw slightly less square and raise his cheekbones. It wasn't much better, but he figured he could pass as half Asian at least, and the changes were simple enough for him to remember. He kept his eye colour the same, not liking the itchy feeling that charms leave on the eyeballs, and his hair was the same colour, only slightly longer and covering his eyes. He was never able to change anything about his hair except the length; it being somewhat resistant to magic for some reason that he'd probably never know.

Looking at his new face in the mirror, it had to be said that he didn't actually look too bad, and without the shadows under his eyes he wouldn't look nearly so washed out.

Nodding to himself, he replaced his wand into the undetectable holster on his forearm, quickly made his way to the underground parking that came with the apartment, and found the car that had also been arranged prior to his arrival. It was inconspicuous at first glance but Harry, or Ryuuki as his first name was now, knew that there were a few magical tricks hidden in there, including enchantments preventing the thought of stealing his car even entering someone's mind in the first place. Didn't work so well on wizards, but it worked wonders on the muggles. Inside the car he found an ID pack, which had his alias filled in already, and would record a passport type photo of his face as soon as he touched it.

Ten minutes later, and the best drive of his life, he was at the NPA headquarters, having decided he liked driving in Tokyo, and to possibly submit a request to buy this car after the case was finished. He walked up to the reception desk and showed them his ID and was directed in turn to a busy room full of people rushing about waving files and wearing headsets.

"Hey, are you the guy that transferred from Okinawa? Kinjo Ryuuki was it?" came an excited voice to his left as he stood watching everything, and the voice carried on without waiting for a reply. "Hi! I'm Matsuda Touta! Pleased to meet you!"

Ryuuki turned to see a man perhaps a couple of years older than he was bouncing on the balls of his feet, with a huge grin.

"Uhm, hi, yes I'm Kinjo Ryuuki, the guy from Okinawa. Pleased to meet you," he replied, dragging his hair over his scar in a nervous gesture. "So this is where it's all happening? Can you bring me up to date, or is there someone I should speak to first?"

Matsuda scanned the room. "We should probably let the Chief know you're here, but he's on the phone right now. He'll be done soon though, but until then I guess you could come over to my desk!"

Ryuuki nodded and followed Matsuda to a small desk filled with papers, staying quiet as Matsuda kept talking. "This is my desk, a bit cluttered I know, but criminals are dying everywhere, and people are panicking and calling in saying they've seen Kira, and we've even had crazy people calling us to that that they are Kira themselves! It's just silly; everyone knows the real Kira wouldn't just call us! We have to make a file for them all anyway though, and it's my job to check their backgrounds. Ah, there's the Chief now, HEY CHIEF!"

An older man with greying hair looked over to Matsuda, and made his way across the room to where they were standing.

"Yes Matsuda? Ah, you must be Kinjo Ryuuki. Yagami Soichiro, but just call me Chief like everyone else round here. It's a pleasure to meet you. If you'll come with me I'll have to take copies of your ID and make sure it all checks out before I can fill you in on what's been happening."

Ryuuki nodded and left Matsuda with his paperwork, hearing a loud "see you later Kinjo-san!" and turning to give a small wave and a shaky smile in return. He followed the Chief to a tidy office.

"Don't mind Matsuda, he might be rather... enthusiastic but he's a damn good shot. He lacks proper experience, though." Ryuuki sat down in the only chair available, in front of the desk, finding it rather strange to be on this side of the desk again. "It says here you've had training, but it doesn't say what you've been trained in and by who, can you explain this?"

Harry leaned forward with his elbows resting on his knees, and an apologetic expression on his face as he spoke quietly. "Well, a few years ago I spent some time overseas, and that's really all I'm allowed to say about it. I signed legal documents stating that without permission I can't disclose any information to any outside party, even if a gun is held to my head. There is nothing untoward occurring on my part; I'm just legally not allowed to tell you."

The Chief looked carefully at him over the top of the file he was holding, and he took his time before replying.

"I've come across cases like yours before in the police force, and every time I've checked them out I find roughly the same thing, very little history and these people don't tend to stay long. I'm going to take a guess, and you don't have to confirm or deny anything. I'm going to guess that you've had specialised military training somewhere, and that you are here to keep tabs on us for some reason or another, although you look a bit too young for that."

Harry looked out the window for a moment, before looking the Chief in the eye.

"I can honestly say that my previous experience has no bearing whatsoever on my presence here today, and that I honestly want to join the taskforce and bring this Kira in. If it came down to it, my skills could come in useful, but it would have to be a life or death situation, otherwise I could be in quite a bit of trouble. It's not right what Kira's doing, and it looks like the only thing stopping Kira from targeting innocent people is that he seems to think he's doing the world a favour." He kept his eyes locked with the Chiefs, willing him to believe him.

"Well, we've never had trouble with any of the others in your situation, and they've been hard workers. I trust my instincts here, and they're telling me that you're a good man. I have a warning for you though; we are not the only ones here investigating Kira. L himself has taken on the investigation as you've no doubt heard, and I doubt he'll be happy with the little background information you have."

Internally Ryuuki froze, realising that nobody had factored in the mystery detective actually wanting to know more than basic information. He supposed it made sense to make sure the investigation team wasn't hiding anything, but he was hiding something huge and the detective would probably catch on to the fact that something was off. If he added false information now, the Chief would know. In the few instances of working with the muggle police in the rare case that there was a magical serial killer targeting muggles, it had been within a short time frame and the main aim was to stop the police from finding out the method used and to be on hand to call in the Obliviators when necessary to keep the magical world safe from discovery. If a magical person died, the goblins were the first to know who would then alert the appropriate Ministry department, and things were mostly taken care of before the muggles even knew someone had died. Good thing really, as purebloods didn't have muggle records.

In this case, it was already extremely public and he had no idea what he was dealing with. Possibly a magical artefact has been found, and is now in muggle hands? He was looking at possibly spending months in Japan, searching for a serial killer whilst trying not to raise the suspicion of this L character, and if L ever found out he was a wizard, he'd be number one suspect.

"You're right Chief, but I'm not really sure what I can do about it. I suppose I'll just have to see what happens. Can you fill me in on what's been found so far?"

The Chief leaned back in his chair, folding his arms, and sighed. "To be frank, we don't have much. We know that Kira somehow kills his victims by heart attack, but we don't know how. We know he needs a person's name and face to kill, because those whose names are misspelled in the media don't die. We also believe that Kira can set the time and date of death, and that he has access to police information. Mainly we just need help putting the information into the systems, putting it in order to try and make sense of it all."

Ryuuki's eyes were as wide as they could get in their transfigured state, barely able to believe what he was hearing.

"And this is all confirmed, Chief?"

The Chief looked at him squarely.

"Yes. That is the information we have. L also suspects that Kira may be a student. When that information was made viewable to the police via the database, the pattern changed from being mostly outside student hours to being one criminal on the hour, every hour. L deduced from that information that Kira could control time of death, and that his suspicion of Kira being a student was correct, and that somehow he has access to the police databases."

The Chief gave him a long look.

"You must be very tired after your long journey Kinjo-san, you should go home and rest, and we'll see you in the morning at 8, and we'll get you started."

Ryuuki gave an uneasy smile and said, "Thanks Chief, although I do have to wonder, Kira must either be trying to throw us off track because L got it right, or he's taunting us, or perhaps both. Either way he made a mistake, and if he keeps making mistakes then we're sure to find him soon."

"That's what we're all hoping Kinjo-san. Go home, get some rest, and we'll see you in the morning."

Both men stood up and bowed to each other, before leaving the office. Ryuuki waved back to Matsuda, who had spotted them leaving, and made his way back out of the building, heading for where he parked his car.

Yawning, he pulled out of the car park and headed for a row of shops likely to sell food that he'd seen earlier on his way to the NPA.

He parked the car, and walked straight past the first two restaurants when he saw what the people sitting at the window were eating. It almost didn't look edible, but people were eating it, and he didn't think he'd find anything suitable in there.

The next place however, looked to be a sweet shop or a bakery of some sort. This looked to at least have something he could class as food until he could ask Hermione what he could eat that wouldn't make him throw up violently. She tended to know obscure things like this, having travelled to many different countries with her parents. He'd have to find something soon if he wanted to pass off as being at least part Japanese.

Sure enough, he could recognise cake when he saw it. The shop was empty apart from one customer, an elderly gentleman standing at the counter. The shop smelled fantastic and Ryuuki found himself leaning down staring through the glass at a strawberry cheesecake like he'd never seen food before, not having eaten since breakfast the day before in England. He hadn't quite realised how hungry he was.

"Ah, I apologise, but the lady who works behind the counter is filling my rather large order I'm afraid. It shouldn't be too much longer I hope."