A/N: I want so badly for this to be porny, but I want to have a serious story at the same time. Please bear with the plot back story for now! (I know I am.)

"Heart of Darkness"

Rin continued to scowl, long after the light in the hall thinned to a mere sliver and then finally darkness as Yukio closed the door behind him. His attention was drawn by the low, dull murmur outside – undoubtedly some conversation with Yukio (about himself, he would've liked to imagine). His ears strained to pick up words – "Professor", "Rin" – his concentration began to wane as he realized Yukio and friend were beginning to leave, their footsteps growing quieter and quieter as they left down the hall.

He waited until it was completely clear to pick up his uniform, dressing as quick as someone swathed in ten different layers of bandages could. The cuts still hurt every time he moved the wrong way, but now that they were stitched up, he didn't run the risk of opening his wounds anymore.

Besides, he consoled himself; both of them knew there was absolutely no way Rin could stay still in bed, even when he was sleeping. There were plenty of times in their childhood where Rin found himself on the floor of their bedroom; it had puzzled him quite a bit since he slept on the top bunk. Yukio, bless his heart, had offered to switch beds with him, fearing Rin could hurt himself sleep-rolling.

He shifted slowly to glance at the clock on his desk: nine in the morning. Yukio would be busy with classes until at least four o'clock (he usually stayed later to run tutoring sessions), and that left Rin with plenty of time to himself.

Rin tucked his tail into his shirt, skipping the tie altogether, and threw his blazer over his shoulder in a hurry, "Ah, crap. Where did my keys go?" He frowned, digging into his pants, fingers fishing for the familiar ring of keys. Rin's frown only deepened as he realized they weren't there. In fact, he looked around the room, they weren't anywhere. "That damn four-eyes must've taken it," he grumbled, "I'm gonna have to take the long way…"

The door to Mephisto's office creaked in protest as Rin slammed it shut, though both paid it no heed. Kurikara swung against him, brushing the tips of his hair as he stopped in front of the wide mahogany desk. Mephisto seemed to sense he was coming, because he already had some confectionaries out.

"Okumura," he drawled, eyes glittering, "come, sit down. To what do I owe the pleasure?"

Rin did as he was asked, settling down into one of the cushioned armchairs, "You know why I'm here – I want to know what went wrong." He distinctly remembered the hike up the mountainside, especially since Yukio had to wake him up so early so they wouldn't be caught up there at night. They were caught up there at night, obviously, since he was attacked a little after evening time. After that, he couldn't think of much, except that the monster that had attacked him as most likely a ghoul. It looked like a mountain lion, slightly larger, which he initially had attributed to bloating; the fur was patchy in some places and the muscle had begun to liquefy in some areas where the decomposition was particularly bad. Rin wondered, exactly how did Yukio get them back to the academy so fast? Where did the ghoul go?

He would've asked his brother had he not immediately gotten into a fight with him. (Rin also got something else he would rather not think about.)

"Tell me, did you read any of the briefs before going out?" Mephisto smiled, crossing his arms.

"Um," Rin looked around sheepishly, "No."

"I'm sure Fujimoto has got you familiar with the seven deadly sins, yes?"

"Er," he paused, "Yeah."

"And?"

He had to think about it, "Well, there's greed, gluttony, vanity, wrath, envy, lust, and…"

"Sloth," the headmaster corrected, "Good, you know them." He waved his hands animatedly as he began to speak, "You see, Rin, for as long as humanity has existed, there were temptations, and –"

"Just cut the crap," Rin interrupted, "What do they have to do with the mission?"

Mephisto held three fingers up. "Three."

Rin blinked at them. Once. Twice. "What the hell is that supposed to mean?"

"You would have understood if you had listened to the introduction," he shot Rin a pointed look, "The three strongest sins, the three basest of sins on which human nature lies. They are the most basic, most carnal of the seven deadly sins: pride, greed, and lust. Are you familiar with Dante's Inferno?"

"Yeah, the nine circles of Hell or whatever."

"The leopard, the lion, and the she-wolf each represent a sin; the leopard – lust, the she-wolf – greed, and the lion…"

"Pride," Rin finished quietly, "Then Yukio and I were… fighting a sin?"

"Sin, like humans, cannot simply be eradicated," Mephisto replied cryptically. Rin frowned; what was he thinking? Did Mephisto honestly think Yukio and him could defeat a sin? Wasn't it kind of, oh, he didn't know, really strong? "However," the man continued seriously, "we may slay physical manifestations of it when they appear, since if these types of demons are left to their own devices, they may affect the people living near it. They'll come back – they always do, but not for a while."

"So the village nearby would've been affected… by what? Pride?" Rin scoffed, "They all start flexing in front of each other or something?"

"Perhaps at first! It starts out small, and eventually turns the people against each other – feuds and things like that," the headmaster waved. Rin froze. He hadn't considered it much until Mephisto had explained it, but had Rin been exceptionally difficult with his brother this morning because he came into contact with Pride?

Mephisto, as though sensing Rin's thoughts, smiled gently, "Don't worry. While the effects are… a little uncomfortable, they're not permanent and they're not too extreme either. In fact, once the sin is slain, the influence it has immediately dissipates."

"What the hell?" Rin slammed his fists onto the table, "You knew this would happen –"

"Yes, I did," Mephisto said, almost smugly.

" – and you still sent us! That's dangerous! Why didn't you tell me?" Or at least, he thought, wards and charms that could have been prepared.

"You didn't ask!" he sing-songed. Rin stared at him, trying to see whether or not the man was serious. "But if you want to know, our branch is being dispatched to kill all three, two of which have been located in Japan."

Rin breathed a small sigh of annoyance.

"Yup, all three," Mephisto continued cheerily, "You should be glad for this kind of field training, actually – it's not something usually entrusted to an exwire. You two should have nothing to worry about – that is, if you're worried about the effects – if you kill them quickly."

Rin mumbled something unintelligible in reply, not at all relieved. It was true that he had been tagging along with Yukio, seeking 'hands-on' experience. It was also probably true that if he wasn't aware of the effects, he'd be excited.

"Hmmm? Is it too much for you then?" the headmaster grinned, "Perhaps you would prefer to pick medicinal poppies with the other exwires?"

"No!" As quickly as those uneasy thoughts came, they went; this kind of work was the break he'd been catching since he came to True Cross. Rin had no doubts if these missions were successful, he would be allowed to rank up. Whatever strange feelings he had this morning was merely a fluke, just a mix of bad medication and drowsiness. He took a breath, "I can do it - leave 'em to me." Though he had to smile sheepishly as he remembered his wounds, "I just need Yukio to get off my back. I'm not even hurt that bad…" Mephisto raised a curious eyebrow, but otherwise said nothing. "So what's next?"

"Well," the man started, observing Rin carefully, "because Pride has not been relocated since –" here the headmaster nodded in his direction, "– you will head on to Greed." Mephisto pulled some papers out of his desk, handing them to Rin. "It has been spotted several times by our scouts near Mount Fuji –"

"That's a huge area!"

"- in Aokigahara."

"… the Suicide Forest..? Why would Greed be there?"

"With the economic downturn recently, Greed has definitely gotten a foothold here in Assiah. It wouldn't be too suspicious with the rise in suicides, but there's been a sharp increase in locals dying as well."

"Right…" The pieces started to fall into place, "So something must be affecting them."

"Thank you, Okumura, for your valuable insight," Mephisto chuckled. Rin grunted, not amused. "Yes, there is something. Locals have been warned from childhood to stay clear of the forest, yet recently, concupiscent villagers have decided to mine for iron ore. There are, as you may know, large deposits both on the floor and in the various caves on the outcrops of the woods."

"And before they could reach it…" he contemplated excitedly, "Something reached them."

A hesitant knock drew their attention to the door, however. An airy female voice filtered through, "Headmaster Pheles?"

"Ah, Asuka darling," he brightened and to Rin, "Sorry, I've got an appointment. Perhaps another time." The boy stood up, straightening his clothes. He looked thoughtful, which was a rare look; it suited him, Mephisto observed. He looked more like his brother this way. "Rin, remember that a good exorcist won't hide his emotions. The sins will only exploit them to hurt you," he met Rin's wandering gaze, "They'll play on that which you seek to hide most."

As Rin exited the office edifice, those words haunted him. "That which I seek to hide most," Rin swallowed. Those were the sort of foreboding words that signaled some great emotional upheaval in all the manga he's read and needless to say, that was the last thing he wanted at the moment. Rin ran a hand through his hair; there was still some time left before the square would be crowded by students eating lunch, so it was a good a time as any to get sunshine. He sat down on a nearby bench, expression screwed in apprehension.

"I can't keep thinking about this," he groaned, tossing his head back. Rin sat there, focusing on the flowers and the cobblestone and the pretty buildings, but all of his thoughts eventually gravitated to Yukio. In fiction (especially shoujo, which he had unknowingly read before, because really – some of the cover art didn't even look remotely romantic), unrequited love is usually confessed abruptly and loudly, usually after some great misunderstanding. Was his love unrequited? Was he misunderstood?

"No way," he muttered unhappily, "That's retarded to the nth degree."

"What is?"

Rin glanced up, partly because of the shadow looming over him, and partly because the voice startled him, "Oh, hey Eyebrows."

"Don't – urgh," Izumo threw her hands up in defeat, "Nevermind; why are you out here?"

"Why are you?"

"If you have to know," she started smugly, "I was chose – "

"Yeah, nevermind. It doesn't matter," Rin said flatly. Izumo frowned, but sat down beside him at a distance. She didn't look particularly different, though her usual ponytails were hiked up, pinned together by a fancy clip.

"Relationship problems, huh?" she smirked, chin in hands. "Don't ask me how I know," she shrugged when Rin opened his mouth questioningly, "Call it a girl's intuition or whatever."

The demon slumped in defeat, "Yeah, sort of… say, Izumo. What if there's this person I like, but they don't feel the same… and there's no way I can confess…"

"Well first, why not? And second, how do you know until you've tried? But thirdly, I'd understand why they wouldn't feel the same towards you," she crossed her arms.

"First? They're… out of my league. Second, I just know. And third, go to hell," Rin grumbled. Izumo stood up and straightened her skirt, probably preparing to go back to class. Izumo was mean-spirited and holier-than-thou most of the time, but she could be compassionate when she wanted to.

"Rin, I would just go for it, but if you're spineless or whatever, you can just suffer," she waved dismissively, then paused, "But if it's you, you'll probably improvise or do something reckless, because that's what you do all the time."

Rin stared at his palms as she left; that was the nicest thing she'd ever said to him since he came to True Cross, even if it was disguised as an insult. "Crap, it's almost noon," if any of the students caught him, it might as well be Yukio catching him, "I'll be in deep trouble..." It wasn't as though he didn't want to stay outside and continue to mope around in the sunlight, but when he weighed the consequences, going back to his room seemed the more comfortable option. After all, Yukio was damn scary when he wanted to be. Rin rubbed his cheek absentmindedly, still puzzled. His brother had never raised his hand against Rin, ever.

He tried as hard as he could to remember if he had felt any different that morning; what Mephisto had revealed to him earlier was troubling to say the least.

"I guess if Yukio won't let me out, I'll just find something to do inside," Rin said loudly, shrugging his jacket off. Their room was still exceptionally dark for noontime, so he shoved the curtains aside to let some warmth in. Kuro, who had been sleeping on the bed, welcomed this new source of heat, curling up at the windowsill. "Maybe I'll make lunch then?" he asked no one in particular, scratching Kuro behind the ears. The cat replied with a soft purr.

'For me?' he asked, twin tails waving lazily about.

Rin laughed, stepping away to wash his hands in preparation, "Sure, Kuro – what do you want?" The demon cat contemplated this, silent in thought. There weren't any towels, Rin realized as he searched; they were all in the laundry at the moment. Usually they would have finished drying by now, but both of them had (justifiably) forgotten to hang them up that morning. Sighing, he grabbed one of Yukio's shirts off the top of the laundry basket; it was dirty anyways, he reasoned.

As he brought it up, no doubt ready to wipe the water running down his neck, he stopped mid-raise. "Woah," Rin muttered. He gingerly lifted the shirt to his nose, sniffing it. There was a fragrance that permeated the cloth: the heady scent of his brother, which he couldn't quite place. It was deep and pleasant and made him dizzy and left him with an ache. He ran the soft fabric over his cheeks, relishing the way it bunched between his fingers. With his other hand, he ran a hand down his stomach, a nail catching neatly on his navel.

Rin groaned into the shirt and imagined it was Yukio. He imagined it was Yukio who was pressed up against him like he was that morning, deft fingers ghosting over his bare skin, slick and gliding.

Rin shuddered with guilt, "Crap…" Just this once and I'll never think about it again. With a quick peek outside to make sure Kuro was busy, he inhaled the intoxicating scent again, this time slipping a hand under his loosening bandages to get some of the salve over his fingers. Somewhere in the back of his lust hazed mind, he realized the deep slash across his chest had already healed quite nicely. The raised gash was now merely a thin line, and there was no doubt the entire thing would disappear in the next hour. He closed his eyes, slumping against the door with a shaky sigh as those sticky fingers left a wet trail down his abdomen.

"I want salmon!"

Rin had never jumped so high in his life.