Prologue

|Disclaimer: I do not own Blue Exorcist/ Ao No Exorcist, nor it's characters. Just this story.

This story is completely AU, well kind of. It's actually based off an anime short called Ura Eku- Ao No Exorcist special 10.|

Astaroth had failed his mission again. It was hard enough the first time he had come back after being exorcised by that damn Paladin but he was sure that he wouldn't would fail to succeed in his mission the second time. There was no way he was going to disappoint his father again by not returning the second time without the young prince. However, his ego interfered with his plans and despite his best efforts, he failed once more. Satan was definitely not going to be very pleased.

"Damnit, Lord Satan is not going to be too happy with this time," Astaroth muttered to himself in shame, "It was bad enough that I didn't come back him the first time but he is for sure going to kill me. I better prepare myself for the worst."

How was it that he, the great Demon King of Rot was so easily beat by the Paladin twice in a row? That bastard had no idea how hard it was to get through to that monastery. Considering the fact that his host had been hurt and that hurt like a bitch. Pardon his language, but he just couldn't himself.

Astaroth wanted so badly to just hide away in his quarters and never come out again, as if to avoid Satan all together. However, Satan was going to catch onto him anyway, so there was no use avoiding him. Avoiding Satan was like avoiding humans when one entered Assiah, impossible. The Demon King of Rot ever so slowly exited his room and headed towards the throne room, where he was pretty sure he would be punished.

"Astaroth… Welcome back, I trust that you have succeeded in your mission to retrieve the prince?" Satan asked, though already getting a feeling that it was quite the opposite, "Speaking of the prince, where is he? I'd like to have the pleasure of meeting him in person."

The younger demon originally thought that he wouldn't feel any worse than he had before but that assumption was wrong. Astaroth once more looked down in shame, afraid to look at Satan's facial expression.

"My Lord, it's harder to obtain the young prince than you might think, he was heavily protected," Astaroth said with a frown, "The boy's guardian, the Paladin, managed to exorcise again and this time he had help. Even the young prince helped him. I really did my best…"

The demon didn't even have to look to know how pissed Satan, not when he could sense it. It felt as if Satan was going to explode him or kill him on the spot. Even worse, what if he subjected him to and endless amount of torture. Astaroth shook his head. No, he didn't want to think about that.

"Are you telling me that you not only failed me once, but you failed me twice?" Satan snapped and stood up quickly out of seat, not hesitating to storm up to the ram-horned demon, gripping him very tightly by throat and lifting him up off the ground, "How could you fail me when you know how essential the prince is to my plans, our plans? It seems that in order to get things done, I have to do things myself… I am disappointed in you, Astaroth. When I come back you will pay handsomely."

Astaroth was struggling as he could feel how tightly the older demon was holding him. The fact that Satan would have to fetch the boy himself showed just how important Rin was. Of course, Satan had been trying for a very long time to get to him but the only suitable host he had was unattainable.

If the younger demon had accomplished anything, it would have been creating a strain in the relationship between the Paladin and the son he had taken in. Doing that could have possibly affected Shiro just enough to allow Satan to temporarily possess him.

Well, he was in some pretty deep shit. If Satan managed to come back with Rin than that wouldn't help matters. It would only show just how much of a failure Astaroth truly was.

Satan was gone quite a while, so while he was waiting Astaroth had spent the time in his quarters thinking about what Satan was going to possibly do to him. The older demons form of punishment was probably the worst thing any demon could experience. Much worse than exorcism.

After hours (because time in Gehenna went by much quicker than it did in Assiah) Satan had finally returned but Astaroth didn't know until the door to his quarters opened up. He took a deep breath and turned to face said demon. However, even he seemed empty handed. Had even the great Satan failed to obtain Rin?

"I must congratulate you on one thing, Astaroth, you at least managed to mentally weaken the Paladin enough for possession," Satan said in frustration as he stepped inside the room, not taking his eyes off of the demon, "That Paladin is a bit of a handful… I had Rin in my grasp but the human surprised me. I was so close until that damn fool killed himself. On top of that, my own flesh and blood destroyed the gate. What a pest…"

Satan was even more pissed than he had been before he left. So, needless to say, he wasn't to concerned about punishing Astaroth when he himself wasn't even able to accomplish the same task. Maybe, just maybe, there was another way to get him.

"I told you that the Paladin was going to be a problem, why would I ever lie to you?" Astaroth sighed with relief as it had seemed that Satan had forgotten about punishing him. "At least the Paladin is out of the way now."

"You're right, the Paladin won't be a problem but the real issue is Rin, he is too strong-will and because of that he destroyed the gate," Satan muttered and clenched his fists before grinning at Astaroth, "You're host. Didn't you say before that he was going to attend True Cross Academy?"

The question caught Astaroth guard. Yeah, he did mention it but what did that have to do with this? It's not like Rin was an exorcist, nor was he all that bright. However, the more he thought about it, the more he could see the connection.

Shiro was gone now and since he was gone he would be under new care. From what he'd heard Mephisto was a good friend and it was most likely that he would be his guardian. The Demon King of Time also managed the school, which meant that there was a chance he would send Rin there to watch him.

Even with the protective barrier around the school, Astaroth would still be able to get inside the school since his host was already there. The barrier only prevented demons from entering from the outside. If he already possessed Reiji, thenhe wouldn't be able to go in.

"That would be correct, Lord Satan," Astaroth said with a smirk, "As we are speaking now, my host is most likely inside the school already."

"Excellent, since this is so convenient, I will give you one more chance but only because of that," Satan replied before summoning a gate, "Even if your host was blessed, it shouldn't prevent you from possess him. I want you to do so, but be subtle about it. No one can know about your presence. Do whatever you must to get him and do not come back until you do."

Astaroth's grin expanded as he simply bowed, "Understood, I will return as soon as I can, and this time I won't be empty handed."

|Well it appears that I've had motivation to rewrite all of my old Blue Exorcist stories, so here you go. Review away!|