Yin: the principle of darkness, negativity, and femininity in Chinese philosophy that is the counterpart of yang. The dual, opposite, and complementary principles of yin and yang are thought to exist in varying proportions in all things.

Yang: in Chinese philosophy, the principle of light, heat, motivation, and masculinity that is the counterpart of yin and is thought to exist along with yin in all things.

L furrowed his brow. Why was it that these two simple words struck a deep chord inside of him? It was a sort of rightness, like this was how it was supposed to be. Yin and Yang… They were just philosophy. Weren't they?

He bit down on his thumb absent-mindedly, staring at his computer screen with increasing worry. For some reason, Matsuda had set off his curiosity, and in that his concern.

The other detective had been lounging near where L and Raito were taking their break (still chained together, of course) and talking to Soichiro. Then, all of a sudden, he'd turned to the detectives with a serious look on his face. This in itself was disconcerting. Matsuda was never serious.

"Ryuuzaki… Do you realize how much you two remind me of Yin and Yang? I heard that story when I was little, and it just seems to fit so well with you guys." After this, he turned back to Soichiro and resumed his conversation. Everyone within the vicinity had been slightly shocked at this observation.

Raito and L had shared a single, confused glance, then L had returned his attention to his strawberry-flavored cake. He dismissed the thought immediately.

Except he hadn't. It was now several evenings later and everyone else had retired already. He was crouching in his usual crouched position, staring at the computer screen. It had been bothering him, so he decided to research into it a bit.

Raito was absorbing more information about Kira. L glanced at the boy, who didn't notice his troubled gaze, and frowned.

The other detective was sitting normally, but his eyes were intent upon the screen. His head was propped on one hand, the other on the mouse. A scowl was on his pale mouth.

He reminds me of Yin, Ryuuzaki mused. It wasn't surprising. Raito was so perfect he could be considered feminine, especially when one thought of his attempts at such a perfect appearance. He was dark, L knew that for sure, no matter how he tried to hide it. L saw the flashes of red in his eyes, the sneers and anger he hid. The hate and scorn for others that hid beneath his otherwise perfect smile.

Negativity, as well. One of his favorite things to do while they were alone was to grumble about how slow everything was. He was very negative most of the time, anyways.

Does that make me Yang? L wondered. That was a good question. Was he…? Surely he was far more masculine than Raito; they had figured this out shortly after the chain had been attached— He had to grin at that thought— but he wasn't sure about the others. His demeanor was dark, wasn't it? But of course, his sense of justice… It was different from Raito's for sure.

"Raito-kun." he said softly. "If we are Yin and Yang, what am I?" Raito glanced up at him, not at all surprised. He was used to these pondering outbursts; L usually asked his opinion.

"Yang." he said, rolling his eyes, "Don't listen to Matsuda, Ryuuzaki. You know he doesn't have a clue what he's talking about. Besides, you're far too masculine for Yin, if you don't remember."

He grinned, running his fingers lightly over L's muscular shoulder. L smiled as well, but remained troubled. "Yang?" he asked softly, "But Raito-kun…"

"Trust me." Raito murmured, leaning over and kissing him chastely, "You are definitely Yang. Do you want me to prove it to you… more persuasively?"

He grinned that devilish grin that L had first fallen for. L found it hard not to flush right then, but he remained nonchalant.

"I don't understand." he said, "Surely I am too dark to be Yang."

Raito threw his head back and laughed. "You, dark?" he cried, "That's a good laugh! You may look like a demented panda from far away, but trust me, you get better once someone gets to know you. You are too nice to be dark, Ryuuzaki… Does that make me dark, then?"

That devilish grin was becoming unnerving and he found his restraint almost broken by those devious, sparkling eyes. "I suppose so." he smirked, "Now that that is figured out… Are you going to take up on that offer of yours…?"

"Of course." Raito smirked as well. Giving L another chaste kiss, he led his partner to their bedroom by the chain.

"Yin and Yang." L murmured as he shuffled behind him, staring at his back contemplatively. "I think you are correct for once, Matsuda-san, in more ways than you can know." And at this, Raito laughed again.