Belief
"the origin of right or wrong has to do with the origin of his belief"
The word 'believe' for L held much stigma, and although the word in itself held no real threat against L, he saw 'believe' as a personal affront to the faculty of reason and to his own intellect. The stigma was faith, that while belief in itself was the complete security in knowledge, combined with faith, it was distorted into something vicious, something potent and addicting. L shared his thoughts with Light on this, with his head facing Light the slightest, with the appearance of never disengaging from the computer screen. In truth, there was nothing in the computers that he didn't know already; he had been over it so many times.
"How then do you explain, L, your fixation on me being Kira?" replied Light, holding no pretence and instead facing L directly. His hands clutched the edge of the table, fingers white from the strain of trying to calm down. "If reason is your faculty, and evidence is your foundation, then what do you have?"
L remained silent for a moment, fork hanging limp from between his fingers, blinking at the screen. He was an outward picture of complete calm, a wall impenetrable, but it was in the way he used three fingers instead of two to grip the fork, it was in the thumb pressing against his lip instead of gnawing. L knew that Light could see the tension in him,. But L had an answer; one he did not want to disclose.
"There is something I believe in, Light, that tells me that you are Kira." Said L, slowly, and the answer was a punch to his own gut since this belief was actually grounded on faith and this faith was something he wanted to be rid of. The resounding silence in the room wasn't broken until the arrival of the team the next morning. The silence continued though, absorbed into the walls, into the chain and under L's skin.
In the turbulence of the following days, when everything just blew over, L was grounded solely by this. The excitement of capturing Kira did not make it to his core; it was shrouded by a dark calm that he refused to examine unless necessary, unless there was nothing else. Light knew too, for he watched L since that night, lips parted and ready to ask the question that's been floating silently between them. He knew L would not respond; he wasn't sure he wanted to know the answer.
It was night when L finally spoke, peering over a slumbering Light who was facing him. The discomfort of the chains had long been erased from him; he was used to it by now. L, though, never got used to the constant presence of the boy, like now. Now, he was perched on the bed, a pale hand resting on the sheets a few inches away from Light's face, feeling the breath ghost over his fingers.
"This world will burn before you Light," said L, "And that's the faith I know to be true. That you will achieve something greater than this." And as L said it, his voice hitched the slightest at the burn inside him.
"And I'll be waiting for you when you fall. That too, I believe you will."