DISCLAIMER: I do not own any of the Yuyu Hakusho characters.

I tapped one of my sheathed daggers impatiently on my knee, taking great care that the Boss didn't notice. I had waited too long for an assignment from the top - there was no way I was blowing it by being disrespectful while he finished his phone call.

I wasn't paying attention to what he was saying to the person on the other end. If it concerned me, the Boss'd let me know. That was how things worked in the Requiem. You didn't overstep your bounds, or you were likely to find your throat slit.

Finally, the Boss snapped the phone down, seemingly pissed off. I leaned back a little in my chair, clutching one of my knives tighter. It wasn't unheard of for the Boss to take his bad mood out of anyone who happened to be nearby.

He took several deep breaths, obviously attempting to calm himself down. I relaxed as well. If he was taking such measure to sooth his anger, then I probably wouldn't end up headless anytime soon.

The Boss was a big man; very muscularly built. He was taller than me by about three feet, which actually wasn't hard considering I didn't even measure five feet myself. He was fairly older than my two centuries, but it didn't show. He could easily still be carded in a bar. I wouldn't call him handsome unless it was referring to the dangerous kind of way. He had a strong chin, exotically tan skin, black hair that was slicked back professionally, and eyes as dark as his hair; eyes that never betrayed any emotion.

"Well, Zen," he said in his deep booming voice, and I straightened up in my chair. "I've got an important mission, and this is your chance to prove yourself."

"Thank you, sir," I said quietly. I'd proved myself time and time again; he just didn't care enough to notice.

"Here it is," he said, handing me a portfolio. I cracked it open, looking at the picture and profile of my next target. A small vial of clotted red liquid also slipped out, and I picked it up. I took the stopper out, taking a big sniff of the blood inside. It smelled of stone, as well as fire and just a hint of beer. A strange combination. I turned back to the papers. While I studied the information, the Boss told me the details.

"He's the Spirit Detective of the Spirit World, Yusuke Urameshi. He's human, although there are rumors that a distant ancestor of his was the great Raizen himself - although we do not know if this is true. He mainly fights unarmed, with the Spirit Gun as his trump card. He's very dangerous, although evidence claims he isn't known for using all of his brain most of the time. He's taken out a great many of my allies, and I want him stopped."

The profile listed Tokyo as his place of residence. If he was as powerful as the Boss was making him sound, then it wouldn't be hard to find him in the vast city. I got swiftly to my feet, snapping the portfolio shut and tucking it under my arm.

"Consider it done," I said softly, turning without another word and exiting from the Boss's elegant office. There was no way I was going to mess this opportunity up.

I tucked a few loose strands of my long black hair back into my braid, restlessly watching the school building. My senses told me the detective was in there somewhere, but I preferred not to draw attention to myself by attacking him right in the middle of class. I was actually surprised he was young enough to still be in school when his aura was large enough to surround the whole building. It sent a shiver of excitement up my spine.

I watched as the detective exited the school before the final bell even rang. I was glad to see that he was alone.

Or was he? As I watched, an unnatural shadow darted from between the shade of the trees, stalking Urameshi. My eyes narrowed. It literally was a shadow - one that I knew well.

Tane, one of the apprentice assassins from the Requiem. Apprentices never got assignments outside of Demon World. What was he doing here?

More so, what was he doing here, stalking my target? I stifled a growl of rage. If he touched so much as a hair on the detective's head, there would be hell to pay.

But I couldn't do anything at the moment. Stopping Tane would mean that I would expose myself to Urameshi. Later tonight, when Urameshi let his guard down, I would confront the shadow demon.

I clenched one of my fists into a ball. I couldn't wait.

For all his power, the detective wasn't rich. He lived in a small, fairly cheap condo with his mother, from what I could tell. It certainly wouldn't be difficult to sneak in and rip the detective's throat out while he slept. Not the most honorable thing, but in the murder business, honor was a rare thing to come by. And too often it got someone killed. But, that would have to wait. Right now I had more important things to attend to.

I hadn't seen Tane for a while. But in the darkness of the night, it was too easy for him to hide. And Urameshi's power was sufficient enough to cover up any hint of Tane's.

I felt it the moment the detective fell asleep. His immense field of aura retracted in order to protect his sleeping body - something human energy did naturally. At the same time, I noticed the presence of two demonic auras. Obviously one belonged to Tane - the weaker one - but what about the other one? The one that was nearly as strong as the detective's?

Emotions battled through me: desire to kick Tane's ass, duty to my mission, and lastly curiosity to find out who this unknown demon was. Curiosity won out.

I dropped from the tree I had been perched in, silently landing on the grass below. My bare feet made no sound as I crept closer to the demonic aura. I was so concentrated on the demon that I didn't even notice Tane's aura steadily drawing closer to it as well.

I melted into some bushes fairly close to the demon. I could see him from where I was, but not well enough to know if I knew him. Attempting to get any closer would be taking quite a risk, but I'd never been one to back down from a challenge. I silently moved around the bushes.

And that was when it happened. About ten feet away from both the demon and I, a spark of power flared. My heart nearly stopped beating when I saw Tane, bolding firing a glob of shadow at the demon.

I swore viciously under my breath, simultaneously charging forward. What an idiot! Tane knew full and well that the number one rule of the Requiem was to never harm innocents!

I shoved the demon roughly to the side. He fell, skidding a fair few feet. I threw up my hand, raising a dreadfully strong energy shield just in time. The shadow ball hit it, spreading out so that my formally white shield turned an inky black. It cracked, falling to the ground in a million dark pieces.

"TANE!" I roared in anger as the shield slowly melted into nothing.

Probably having a faint idea what I would do to him if I caught him, Tane dissolved into a shadow, speeding away across the night sky. I swore again, mentally promising myself to deprive him of his manhood the next time I saw him.

I turned to the demon who was getting back to his feet, beating dirt off his long black cloak. He was standing under a streetlight now, and my silver eyes widened in shock when I saw who it was. A second later, my face cracked into a large grin.

"Well, if it isn't the infamous Hiei!" I said brightly, pointedly ignoring the angry glare he sent my way. "Been a long time, old friend."

"I've never used the word 'friend' in reference to you, Zen," Hiei said coldly. "Usually more fitting terms spring to mind, such as 'annoying,' 'anal retentive,' and 'a bitc-'"

"It's good to see you too," I interrupted, just a little icily. "I'd have something I'd prefer to direct your attention to, however."

Hiei's blood-red eyes narrowed. He was still suspicious of me. And probably had good reason to, considering I'd tried to kill him last time we'd met.

"That was a shadow projectile," I continued, undeterred. "We all know that no matter how weak it was, shadow is very well able to kill any other elemental demon, such as fire demons…"

"Where are you going with this, Zen?" Hiei snapped impatiently. I grinned mischievously.

"Well, you know what happens now…If a demon saves another demon's life, the second is in the first's debt until he can compensate her. It's an ancient demon law." I laughed lightly. "And it seems I just saved your life."

"Given that you've tried to take it in the past, I'm not sure that counts for much," Hiei hissed.

I shrugged casually. "Doesn't matter. I still saved your life."

Hiei's upper lip curled, exposing small fangs. "Then how about I let you leave here with your head still intact? Would that count as suitable payback?"

I growled quietly, deep in my throat. "I'm much faster than you, Hiei. You know that. I can be out of Tokyo and halfway to Fiji before you could do anything to me. And then you'd still be in my debt."

Hiei snarled angrily, turning away. I hid my smile of satisfaction, determined not to piss him off further. We both knew I had won the argument.

Hiei whirled around suddenly, grabbing my wrist. I sensed no true malice in this sudden attack, and didn't even attempt to fight back. I merely stared at him.

"Come on," he hissed, his face only inches from mine. "I've got a friend I'd like you to meet."

Thanks for reading. I hope you liked this! Zen is one of my favorite characters that I'd created, so I really enjoyed writing this story. Please be civil in your reviewing!