Author's Note: I've had this one in my head for quite some time. Yeah, I'm taking some creative licenses here, but still, it's amusing to a nerd like me.
What if L had been a little more subtle in his declaration of his identity to Light?
It started on the first day of class. There was that new kid, the one who had scored as high as Light, the "natural born genius", as others were calling him. Light knew better than to try to butt heads over something like test scores, and only offered polite smiles to the black-haired, blank-stared creature. He needed to keep his mind clear and sharp, not full of petty thoughts of being the smartest.
The kid had introduced himself at the start of class, along with all of the other students. Light only remembered his name because he shared it with a celebrity. It was then that things started going wrong.
"Since today is the first day, we'll keep things fun. How does that sound to everyone?" the teacher asked eagerly, beaming at the students. No one gave her any response. Slightly crestfallen, the woman continued, "I'll ask some general knowledge questions. No, they won't all pertain to this class; what's the fun in that? Some of these questions will be worth bonus points, so here's a chance for some of you to get a nice point buffer!"
Light silently huffed, leaning his chin on his hand and staring out the window. He didn't need to show off and he didn't need the points. It looked as if he could spend this class scheming.
"What's the capital of Peru?" the teacher asked brightly.
Lima-- "Lima." Almost as fast as Light had mentally answered, a voice rang out. He looked over at the rest of his classmates. They were all staring at the new kid, that hunched over creature. He was sitting with both feet on the chair, knees up to his chest, thumb placed to his mouth.
"That's right, but raise your hand before answering."
"Oh. Sorry," he said smoothly, obviously not the least bit repentant.
"If you can tell me one fact about Lima, I'll give you five bonus points." Light, over his initial surprise, resumed staring out the window. Now it'd just be a race for points, probably dominated by that "natural born genius". And if the questions were that easy, there was no use trying to compete.
"Heh, that's a pretty smart kid, don't you think? A genius, like you, Light," Ryuk said, smirk in his voice. Light huffed again and closed his eyes. Of course he couldn't reply to the shinigami in the middle of class, but even so, he doubted he would've. As usual, Ryuk was only trying to bait him. "What was his name again? Hideki?"
That piqued Light's interest. He turned with a new eye over to the new kid. Ryuk, asking for someone's name? When he could see their name? …Interesting. It's an alias, he thought. True, in Kira's budding society, it was helpful to use a fake name. But doing so required great forethought and paranoia. And genius.
"Another fact, hmm…" The boy pretended to think, his unblinking eyes never leaving the teacher's. "Well, in the phonetic alphabet, Lima is the word for L."
Several people turned and stared as Light's chin slipped out of his hand and slammed onto his desk.
When he had recovered himself, he was trying his very hardest not to openly glare at the other genius. He, for his part, didn't bat an eye and kept staring at the teacher.
Light was distressed to find that the other genius, "Hideki", had the same Literature class as well.
Still, the teacher was a no-nonsense type and handed out homework and books the first day, so it thankfully didn't leave him much time to brood. He glanced at their first book, one of the "great classics", Les Misérables. Light rose his hand, and when called upon, flatly stated, "I have already read this book, sir."
"I have as well."
He was annoyed to find that the Hideki creature also had his hand in the air. Behind him, Ryuk snickered.
The teacher didn't take kindly to either of them. "Oh yeah? Then recite your favorite lines from the book." It was a ridiculous request, but Light was all too happy to reply. Not only could he test the waters with that other guy, he could also show the teacher that he wasn't one to be stuck with assignments he had already finished. As if to further annoy him, the teacher smirked, and allowed, "You may paraphrase if you wish."
" 'Fantine's tears could have moved a lesser man; her tears could melt a heart of stone, but were powerless against a heart of wood.'," Light recited, trying very hard to keep the venom out of his voice. The man was testing his patience.
That seemed to satisfy him, however, because he mumbled something about accepting it and backed down. He obviously didn't expect anything from "Hideki", at any rate.
" 'It was She.'." "Hideki" spoke up, anyway.
"That's not a line unique to the book," Light muttered under his breath.
"I know that. But the context it's used in is." For the first time since their brief, initial meeting, the black-haired, blank-eyed creature turned to him. He continued (as if Light needed an explanation) in his bored drawl, "What I find interesting is just after that line, Marius remarks about the word 'she' being three letters long. Which it is in English, of course, but the book was written originally in French…" Light suddenly felt cold. The creature continued to stare at him, black eyes watching his face for any sort of reaction. "And the word for 'she' in French is four letters long, elle."
Elle. L. Again. Light kept his face neutral this time, staring back at him until he was able to politely look away. On the inside, however, he was sweating and starting to panic. L. The genius detective who was supposedly closing in on Kira. It looked as if he really was closing in. Relax, relax. They don't have any evidence without the Note, he told himself sternly. It couldn't help the anxiety he felt, though.
Predictably, "Hideki" was in the rest of his classes. Light had had to suffer through more not-so-subtle L hints, all the way through Chemistry, his last class of the day. He was already racking his brain for ways L could be incorporated into any sort of science. There were the abbreviations for length and liter, but that was all he could come up with without getting into some pretty obscure sciences. He might be safe for this class.
"There are numbers any student should know. Pi, for instance. You, recite the first five digits of pi." The teacher pointed imperiously at Light.
He stood up and said, "Three point one four one five nine." Pi was easy. He could do pi. It was that damned "Hideki" that was wearing him down.
"Very good. You, tell me the value of i." She pointed at another student, who dutifully responded, "The square root of negative one."
This was easy. They were only going over basic numbers, probably some sort of review. Just as Light was beginning to relax, however, the teacher pointed at the genius creature and demanded, "Avogadro's number."
"Six point zero two two times ten to the twenty-third power, all over mol. Or it has the unit of negative moles, which is the same, in essence. Its symbol is L."
"Teacher, I am going to be ill," Light announced, standing up.
L watched as Light Yagami marched stiffly out of the room. If his predictions were correct and Light were Kira, he could, in theory, be going off to kill L. But he doubted it; he needed a face and a name. So while he was putting his own life on the line to prove a point to the investigation squad, more of him was just amused at messing with Light's mind.