AN: The beginning of this story takes place after Reikai Tantei managed to save Yukina, but before the Dark Tournament.
Yusuke was sleeping peacefully after another successful mission and was dreaming (having nightmares) about his training with Genkai, causing his eye to twitch slightly in his sleep as he mumbled incoherently about "sadistic grannies". Yusuke's "peaceful" slumber was brought to a jarring stop when he was abruptly woken up by Botan who was "gently" shaking him to rouse him from his sleep.
"Yusuke...Yusuke...wake up...WAKE UP YUSUKE THIS IS IMPORTANT!" Botan shouted as she "gently" shook the Spirit Detective awake.
"Huh? Botan? What the hell are you doing here? Goddammit, I was sleeping!" Yusuke yelled furiously at the blue haired reaper, confused by her sudden appearance.
"This isn't the time for sleep right now, Koenma's got another case for you an-" Botan spoke urgently and quickly, silently wishing that Yusuke would just listen and do as he was told for once.
"Another one?! I just solved one for that stupid baby! Can't this wait till morni-" Yusuke shouted indignantly, jumping up from his bed.
He was, understandably, angry since it was 11 'o' clock at night and it was the weekend. Between juggling his job (which he wasn't paid to do) and junior high (which he skipped 90% of the time), Yusuke was wiped out and felt like he deserved some R 'n' R.
Okay, Yusuke did deserve a break for fighting (and almost dying) the Toguro brothers and their demon triad. But it'd been a week since the fight, which was, in the eyes of Reikai, plenty of time for him to rest (well…in reality, it's not a lot of time, but when one considered how little strenuous activity Yusuke actually does, it is) especially since he doesn't really do much besides skipping school as much as he can, play games in the arcade and beating up some other (normal) teenagers his age (and older). Plus, for Yusuke, fighting normal, and more importantly, human teenage boys was not difficult before he died, much less now. So really in the grand scheme of things, Yusuke moaning about his work wasn't entirely justified. (In the eyes of Reikai and Botan). However to Yusuke, who was a lazy slacker, it was perfectly justifiable for him to kick up a fuss about being ordered to work in the middle of the night. (Not that Yusuke would ever actually admit to being a lazy slacker, but he'll never dispute it.)
"No Yusuke, it can't! Koenma said that this case is of utmost importance! Kurama and Hiei are already with Koenma already and we cannot waste any more time waiting for you!" Botan interrupted Yusuke, she was tired of his whining already and wished that Yusuke would actually think about his responsibility as Spirit Detective for once and just understand that Koenma needed his help. Yusuke, surprised by Botan's outburst, grudgingly agreed.
This was mostly because he actually valued his hearing and didn't want Botan screeching at him so late at night. He wouldn't be surprised if she had woken his relatively new neighbours with her caterwauling, which didn't bode well for him because they could potentially spend the rest of the night or the next day asking his hungover mother why they heard a girl screaming in their flat, or alternatively call the police because they might think that someone is being murdered. That being said, Yusuke was a little curious to know just what was important enough for Koenma to call him so late at night.
After (reluctantly) agreeing, Yusuke told Botan to wait as he dressed and left his flat to go wake Kuwabara (all while complaining every few minutes in his loud and obnoxious voice).
~mini time skip~
At Koenma's office
"Alright pacifier breath, what's so important that you woke me up in the middle of the night?" Yusuke asked
Ignoring Yusuke's insult, Koenma got straight to the point and brought up the image of a young male around Yusuke and Kuwabara's age who wore light blue and white Chinese style fighter clothing (similar to the ones Kurama wore in the Dark tournament only it has a hood) with the hood covering the majority of their head leaving only their face and black fringe visible. The male appeared to be quite short with pale skin which made his dark hair stand out even more. One of the most striking part of him was the red marking on his forehead, just above his eyebrows that was in the shape of a Chinese lotus blossom. The other was his heterochromia eyes, with the left eye being a deep green and the other a beautiful dark blue. His eyes were larger and wider than the eyes of most men, but were narrower than a females. Overall, his face was well proportioned and rather androgynous, but his figure was a little feminine as it was slim and lithe. In Yusuke and Kuwabara's opinion, they looked even more feminine than Kurama. Actually, Yusuke and Kuwabara assumed the person on the screen was a guy, and they would never actually say that Kurama looked like a girl to his face.
"This apparition is Ren, according to our files and is rumored to be a Sacred Spirit. This would usually mean that he's from Spirit World, but what little we have on file about him isn't exactly well documented. Some of our sources from the file claims that he is a demon from the Makai, not a Sacred Spirit." Koenma began, and looked, despite his incredibly youthful appearance, stressed with dark circles beginning to form under his eyes.
"Woah, hold up!" Yusuke blurted out with his customary frown of anger mixed with confusion.
"Yes Yusuke?" Koenma replied with a deep breath, a reminder for himself to be patient with the fourteen year old spirit detective.
"Uh, what's a Sacred Spirit? And what's the difference between a spirit and a demon?" Yusuke asked. This kind of question had been nagging at him for a while since he was sure that Kurama and Hiei were demons, and Botan was the grim reaper (but not considered a demon) and honestly no one had stopped to actually explain the difference in race, if there was any.
"Well Yusuke, a Sacred Spirit tends to be or usually are the children of the older spirits in Spirit World or the ancient 'Gods' of Ningenkai. Those gods are from the oldest and strongest spirits in Spirit World their equivalence for human standards would be Celestial beings. Now normal Sacred Spirits, and I'm using this term quite loosely, are bound to different shrines in human or Spirit World or to stronger apparitions in Spirit World." Koenma said, beginning his explanation. "Are you following me so far?" Konema asked, trying to minimize the amount of questions caused by Yusuke or Kuwabara's confusion.
"Okay, yeah I'm followin'." Yusuke said, while Kuwabara nodded.
"Good, now, Sacred Spirits are contractually bound to the shrine or apparition until:
The God or Shrine owner, or apparition dismisses them.
The God or shrine itself become dilapidated due to no one believing in the God anymore.
They die while serving the one they are bound to.
In the rare possibility that they go rogue, and kill the one they are bound to and leave." Koenma finished looking at Yusuke and Kuwabara, waiting for them to process and understand the information he has just told them.
"Has Ren gone rogue?" Kurama asked, frowning slightly in apprehension. He knew that killing an apparition that was of God status in Ningenkai was a great offence, and if Ren was successful in doing so, he would be a formidable opponent.
"Thankfully no, well at least I'm thankful right now anyway. In order for Ren to have gone rogue, then he would have had to be in contract with an apparition or shrine that we are aware of and, from our research, no shrine or apparition in Spirit World has undertaken a contract with Ren." Koenma explained to the fox spirit.
"Then why the hell are we here?!" Yusuke shouted in frustration.
"If you let me finish, you'll find out." Koenma said rather tetchily, sucking on his dummy, making tsking sounds at Yusuke's impatience. "The reason why I have called you all here is not for Ren's crimes."
"WHAT?!" Kuwabara and Yusuke shouted in anger and surprise. "You mean you woke us up for nothing!?"
Botan blinked in surprise.
"But Koenma, you said this was a matter of great importance…If Ren hasn't committed a crime, then why…" She asked in confusion.
"Because in reality, Ren's files in Spirit World are…there's so little information it not even be a file. According to Spirit World, he has committed no crime, yet he has been imprisoned here in Spirit World for centuries under my father's orders in the highest security cell we have, even the three treasures don't get as much security as he does." Koenma sighed, suddenly looking centuries older than he appeared. "However, 10 years ago, somehow, Ren was able to escape and, although he was weakened by the escape, he managed to disappear somewhere within Ningenkai."
At this statement the Reikai Tantei's heads all turned sharply to stare incredulously at Koenma while Botan stood open mouthed in shock.
"He was able to escape." Hiei stated as he shared a look with Kurama whose face was unreadable and looked back at the toddler prince. Hiei couldn't help but feel a little impressed if Ren had escaped the cell Hiei was thinking about. Holy Talismans to trap both demons and spirits, chains that restrained and sucked an apparitions spirit energy and round the clock security. Although, Hiei did scoff at the security, what little they had, in Spirit World.
Koenma closed his eyes in worry as he continued. "Yes Hiei, he was able to escape unharmed despite all the holy talismans that we had used to contain him."
"So he escaped, big deal, I don't see why you're so anxious about." Yusuke scoffed, right now, he didn't care if a dragon had escaped, Koenma seemed to have woken him up for nothing and he wanted to go back to sleep.
"Shut up Urameshi! Can't you see that this is important! If he could break out of prison, who knows how strong he is?!"
"If Ren has escaped for so long, why wasn't Ren apprehended at the time? Surely it would have been wiser for you to take advantage of the situation and his weakness?" Kurama asked, his brows furrowing, something about this case didn't make sense and it didn't sit well with him.
"I honestly don't know." Koenma admitted after a few moments with a deep sigh. "At the time there was so much hullaballoo about his escape but when I started making preparations to send people after him, my father stopped me. Even a few years ago, when I suggested that we go after him, my father just ignored it, like he didn't even want to think about it. But now he's ordered for Ren's retrieval."
"Well that's stupid." Yusuke said, stuffing his hands into his pockets.
"Yeah, makes more sense to get 'em when they bust out." Kuwabara commented lowly after he had calmed down.
Hiei silently agreed with the two of them. 'Looks like the two fools are using their heads for once.' He thought and wondered, for a moment just how long this moment would last, silently scoffing when Kuwabara opened his mouth to speak.
"…So…What do you want us to do?" Kuwabara asked after a few moments.
'Apparently not long.' Hiei thought, unsure whether he should be annoyed or disappointed by his stupidity…or both.
"I, or rather my father, needs the four of you to track down Ren and bring him back here." Koenma answered him looking the group in the eyes, before looking away.
After a few minutes of silence, Yusuke and Kuwabara agreed to find the missing "convict" and turned to return back to their homes, sleep and start searching for Ren in the morning. Hiei and Kurama waited until Yusuke and Kuwabara had set off with Botan before looking Koenma's in the eyes and began their inquisition.
"What's the real reason we were called here Koenma? I know you don't want us to just capture him. Besides, you have told us nothing about this Ren, what are you hiding from us?" Hiei 'asked' (demanded). His gaze, along with Kurama's was so intense that Koenma couldn't continue looking them in the eye anymore. Koenma looked back down to his desk with his eyes closed, choosing his words carefully before steeling himself and looking back up to the two demons.