Disclaimer: I do not own Kuroshitsuji, D. Gray-man and the characters in it. If you recognize anything in this story, it's not mine.

Warning: Spoilers for D. Gray-man. I've watched the anime up to episode 44, but I've come across my own spoilers and I changed them for my own benefit.

- Shadow Walker -

It was raining.

Allen loved the rain. He loved how it gave life to the world around him and how it coloured the leaves of the trees a glowing green. He loved how it freshened the earth and air, leaving a melody behind that was simple, soft and calming. And he loved how it brought him peace. It comforted him, caressing his face softly, as if regretting it would never be able to wash away his sins.

He loved how the sky cried for him, when he himself couldn't anymore.

It was in the company of the rain that he walked through the empty streets of a small town. The darkness and the rain had chased the humans back to shelter. Allen didn't mind. He had nothing against humans, but their music was always chaotic. It confused him and challenged him to try and understand the humans. But Allen had long given up hope to understand them. There was only one thing he needed to do now. Figuring out humans was not that.

There were no lights on, except for the few windows that weren't covered. Allen had a hard time trying to see what was on the street, but he didn't need his eyes. His ears guided him. They guided him out of the town, into a dark forest. He walked for hours, not knowing where he went. The only thing he knew, was his destination. The reason for his very existence. His sin. And he was there to fix it.

He halted at a door and blinked slowly, turning around. He had not realised he had passed through a large gate, crossed a large square with a fountain and walked a small stairs to a large manor. Apparently he had arrived at a noble's home. That was just fantastic. Allen did not feel like handling an arrogant and pompous man. He had had enough of those. Perhaps he could just sneak in, do his job and leave quietly. Then there'd be no trouble. He hoped.

Allen had just started studying the large building, looking for ways in, when a dark melody reached his ears. He halted. It was unlike that of the demons, but it was also unlike any human melody he had ever encountered. Violins, the cello and the organ were the instruments that were the closest that could come to this piece of music. The Musician was reminded of thunder and a raging sea. The music was loud and close. Dangerous! his mind screamed at him. He wanted to take to flight, but he was rooted in place. He was caught.

His ears heard the creak of the wood, as the door opened. It showed what most people would see as a handsome man with raven hair and striking features. Allen, however, did not notice this. His ears were filled with this horrible tune and he was glad he had covered his head and face against the rain. It gave him a moment to get his bearings back.

"May I help you?" He was dressed as a butler, but there was something evil in his eyes. Only a bit different from the monsters he had faced. Allen almost shook his head, but refrained. He needed to calm down. There was something he needed to accomplish. This human needed his help. He was no danger to him. But that melody gave him the creeps.

The butler cleared his throat, startling the Exorcist into reality. The man had a glint in his apparently red eyes. There was a polite smile on his face and Allen realised he was waiting for something. Something he was supposed to do. Like… talk.

"Eh, I apologize if I have disturbed you," he spoke slowly. His mind raced. What was he supposed to say? "I… seem to be lost. Could you perhaps point me in the direction of London?" Yes, he needed to get away. He would come back later and do his job quietly, and without being seen.

The butler studied him, before once again smiling politely. He opened the door further.

"Please come in. I will draw you a map." Allen started.

"Ah, I do not wish to disturb your peace. If you could just point me the direction, I will be out of your hair." He had hoped that would be it, but the butler didn't seem to think so.

"My Master would not wish me to leave someone standing in the rain. Please come in. I will draw you a map and prepare some tea for you, while you wait for the rain to let up." Allen really wanted to protest, but the melody changed. A melody had never changed before. Never. The Musician was mesmerized. And against his better judgement, he let the hand on his back guide him into the mansion. A terrible feeling rushed through him. Well, at least he was inside now.

The butler took his coat. Allen could feel the eyes on him and blushed. He knew what the man was looking at. Somehow he was thankful it wasn't his cursed scar.

"That is quite an impressive uniform you are wearing," the raven-haired man said as he led him to a small room. "May I ask what it is from? Are you perhaps from the military?" Allen smiled nervously as he looked down at his dark blue coat, embroidered with silver. It would not come close to the uniform he had when he was with the Black Order, but at least he still had his silver rose cross.

"Military?" he repeated. "No, I'm not from the military. This… this is just a memento." Lenalee. Lavi. Kanda. Miranda. Krory. And so much more memories. His eyes glazed over, lost in his past. The black-clothed man let him be. He left the room and came back only seconds later, carrying a tray with a cup and a piece of paper. He placed the cup before Allen and slid the paper towards him. The Exorcist was startled out of his thoughts and blinked at the paper. Then he gently took it and concentrated on it. Why had he asked for a map to London again? Before he had the answer, the butler had asked a question again.

"My name?" he repeated owlishly. "It's Allen." He didn't think to give a false name. It had been a long time since he last used that name. He didn't expect to use it again, or for people to recognize it. The butler moved to stand next to him.

"Allen," the man rolled it over his tongue. "And what do you do for a living, Allen?"

"I'm an Exorcist." Allen froze. He didn't know that habit was still there. That could bring trouble. Allen took a quick glance at the man, but to his relief, he only found confusion. He had missed the look of surprise. He decided that if the man didn't know of the exorcists of the past, he could take a chance. "I hunt demons."

The melody turned even darker, but Allen had somehow expected it. There was a smile on the butler's face. It could have been taken as mockery.

"And you believe there are demons in London, Allen?" The butler was looking at him intently, but polite. His face gave no indication of the melody his music formed. The Musician was suddenly angry and frustrated.

"Humans cannot distinguish them from other humans. But I can see their soul." He stared the man in the eyes, determined and realizing why he was here again. The man stared back, eyes narrow. "And may I ask your name, sir?"

"It is Sebastian. I am the butler of the Phantomhive Mansion."

"You seem to be the only one here. Is the family that lives here not at home?" Sebastian straightened from his bow and poured him another cup of tea. His smile had disappeared and Allen could not read his face.

"Only Young Master, the maid and I live here." Allen tilted his head. That was convenient. He said something else entirely, though.

"Then you do a good job. You must work hard to keep all of this mansion clean and serve your master at the same time." The man did not answer and Allen did not ask further. He finished his tea and placed the cup back on the table. He stood up, the piece of paper grasped in his hand.

"I am afraid I have waited too long," he said. His job could wait no longer. It would have averse affects. "I should leave." Sebastian said nothing, but cleaned the table up. He walked him to the door and let him out as gracefully as a butler could. Allen said his goodbye and thanked him for the tea. Again, the butler said nothing. With a bow, he closed the door behind the Exorcist.

Allen sighed. Somehow he was happy he had left the mansion. But he would have to get in again, without being seen.

He had not taken three steps away from the door, when a gunshot sounded through the air. It was accompanied by a note of thunder from the butler's melody. Allen whirled around and finally allowed his eye and Crown Clown to activate. His Innocence gave him a boost up. As he flew through the air, Allen located the window closest to the demon and grasped its frame. Next to him stood a young boy, one eye wide with shock. The other was covered with a black patch. The gun in his hand was still trembling.

The Exorcist immediately located the butler in front of the boy. How had he gotten up here so fast? His eyes widened when he saw the man's face being covered by black stars. Damnit! Why hadn't he just acted sooner? Then this man wouldn't… He shook his head and turned to the only other occupant of the mansion. The maid. Or, the one who had killed the maid. Allen didn't stare at the captured soul as he used to. Instead, he pushed himself from the window, past the young boy who twitched violently at his appearance. The level two stopped its attack on the butler.

Allen stared past the claws hanging in front of his nose with an unreadable look on his face.

"You would dare attack your master?" he asked with a low tone. It was just a level two, though undisguised. It was odd, Allen mused, that the demon had almost no characteristics. Its body had the form of a human, but with skin of silver and without the details. It was like a human had put on a full bodysuit and flattened his face. The claws and the reptile-like legs were disconcerting, though.

The demon hissed. Allen ignored the fact that it was simply impossible for it to do so without a mouth. He had seen so many odd things that this didn't surprise him. In fact, he had sort of expected it.

"Exorcist!" the voice rasped with disgust. Apparently, it had no knowledge of his other half. That was surprising. Perhaps it had never seen a Noah before, Allen mused.

"Yes," he replied. "I've come to free you." He raised his left hand, one talon extended. "I will end your suffering, so now you may go to the place you– " He had expected an attack. Just not that it would not be aimed at him. Crown Clown rose and wrapped around the sharp spikes the demon had shot with his claws. There was just one that had escaped his grasp. Allen's eyes widened.

When had that butler moved in front of the boy?

Crimson blood coloured the carpet. The raven haired man crouched defensively in front of the boy, one hand at his chest, where the metal had impaled his flesh. Blood red eyes narrowed at the Exorcist. A smirk was on the man's face, a pentacle on his left cheek. Allen swallowed dryly. He still couldn't look dying humans in the face.

"You should focus more on the fight," Sebastian spoke. No! The Exorcist whirled around, but the demon was already gone. He gritted his teeth. So it could make itself invincible? That would not make a difference. His eye located the demon the same moment his ears were filled with a screeching tone. He turned and held up his arm.

The demon glowed the moment his talon touched its forehead. Allen wasted no time and drew a cross. The demon faded away and a soul was released. He smiled at her. She sure was a beautiful maid. The girl did not smile back. She only gazed at him with hollow eyes until she was gone. His smile was replaced with a frown.

As his anti-demon weapon deactivated, the Exorcist gasped. A stinging feeling had appeared in his stomach. It spread down his body, numbing his legs, before deepening in pain. Hot needles entered his skin. Allen screamed in anguish.

He was burning from the inside. He was burning alive!

He stumbled around, embracing himself. It burned! Water. He needed water. His legs carried him away, going to the window. There was water outside. The fountain. He wanted to jump down and find something cool, when suddenly his arm wouldn't move along with him. The boy was holding his sleeve, looking at him in determination. No! Damn it, he needed to move! He didn't have time! He was burning! He wanted to tell him to let go and opened his mouth, but no sound came. His throat closed.

Breathe, his mind told him. He needed air to speak. Breathe!But his chest wouldn't move. His lungs weren't responding. Breathe, damn it, breathe! His heart thundered in his chest and Allen tore at his skin in desperation. Air! He needed air! His fingers were wet and his throat hurt, but he didn't notice. He only knew the little bit of oxygen travelling through his windpipe. A hand slammed on his back and he fell forward as his throat was cleared and blood spattered on the floor.

The world was silent. There were no melodies and no sounds a human could hear. The only thing Allen could hear, was the sound of his own breathing. He realized his eyelids were heavy.

"Sebastian," a voice called. "Bring our guest to a room."

Allen felt himself being lifted from the ground and watched the hazy ceiling move.

"And clean this mess up."

All existence in the world is accompanied by music.

Every object or being releases various notes. Put together, these notes form a melody so unique, that Allen is sure has never been created by man. Humans simply don't have the creativity. As every object has its own variation of notes, there are many melodies existing in this world. Listening to them all at the same time, would make one go insane. It is the reason humans don't listen to the music surrounding them. Even Allen, who is not completely human, would never open his ears to all of the music in the world.

So Allen had a tight control of his gift. He did not know completely how he did it, but usually he just ignored the tunes reaching his ears. Now and then, he would open his ears to nature, but most of the time the only melodies he listened to, were the exceptional ones. The rain was one of them, but it was not the one that intrigued him now.

The one currently keeping his mind busy, was the melody of a certain butler. At first, he had thought him to be a new level of demons. Like those of demons, his melody had a dark tune that was sure creepy. It would certainly have explained how the man had been able to move while being poisoned with demon blood. Allen had quickly rejected that idea. Though Sebastian's melody was dark, it lacked one thing: the Screech. Every demon Allen had encountered had a note in its melody that represented the agony their soul was in. It never stopped playing, wailing in the highest possible pitch and hurting Allen's ears. And that was why he had dubbed it the Screech.

The Screech was how Allen managed to find the demons left on this world.

Sebastian couldn't be one of the demons the Millennium Earl had left on earth. But that left the Musician with a mystery. What could the butler possible be? He could be human, but Allen highly doubted that. He had never come across a human with a melody this dark, and he had met many dark figures in his travels. Even more puzzling was the fact that Sebastian's melody did not stay the same. Melodies didn't do that. They weren't supposed to change.

It left Allen wondering.

As he had just woken up in an unfamiliar bed, Sebastian's melody was not the only thing that left him wondering. He hadn't panicked, when he woke up, as he was used to waking up in different places. He did not know how he had gotten there, though. It had been the butler's melody that confirmed his suspicion of being in the same manor he had fought the demon. The butler's melody was not the only one close. There were five other melodies, one of which Allen recognized as the boy who had been attacked by the demon.

Sebastian had said earlier that he, the maid and the master were the only ones in the manor. The maid was now gone. That left two people, while his ears told him that now five people were inhabiting the house. Had they called people in because of the demon? Or because of him? It would not be the first time people feared him after seeing his Crown Clown. Many times he had had to flee with guns aimed at his face. They were not experiences Allen liked. He did not really feel like going through that again.

So Allen sat up from the bed. He quickly found his cloak on a dark wooden dresser and put it on. His gloves were pulled from his pockets. Allen stared at his left hand. Perhaps these people weren't afraid of him and he could stay. The boy looked like he had seen enough to make him lose one eye. Maybe he wouldn't shrink away from his deformed hand.

The Exorcist shook his head and scolded himself. He quickly slid the gloves over his hands and slowly walked to the window. Looking down, he calculated. He could probably land on the ground without breaking a leg, but he wouldn't take the risk. The tree next to the window was far closer than the ground. He could easily slide down. Allen nodded to himself and made to open the window. Then he froze. With his face so close to the window, he could see his reflection clearly. There was something missing.

His rose cross was gone.

Allen scowled. He was not leaving without his only memory of his friends. That meant confronting the people in the manor.

A crashing sound startled him out of his thoughts. Allen turned to look at the door. The crash had been close. A melody of one of the people he was sure was human, was just outside his door. He sighed. He could start now. So he walked to the door and grabbed the knob. The door wasn't locked. They probably thought it wasn't necessary.

A young woman was standing, staring hopelessly at a cart that lay on its side against the wall. A cup of porcelain lay scattered in pieces on the floor. The cake had survived, though. When the woman noticed him standing in the doorway, her cheeks turned red in embarrassment.

"I'm sorry!" she stumbled. "I wanted to bring you tea and a piece of cake since you have been sleeping for such a long time, but I lost control of the cart and it crashed. I'm sorry, I'm such a bother." She looked completely put out. Allen stared at the cart, wondering how one could lose control of such a thing in such a large hall. Had she been riding on it? He smiled at the image.

The woman was still staring in shock at the cart, so Allen decided to help her. He kneeled and began to gather the pieces in his hand. The woman, who was probably the new maid, shook out of her stupor and began to protest. She followed his example and too began gathering the porcelain.

"Oh please, don't worry, I'll clean it up. Mr. Sebastian said you're ill, so you shouldn't stress yourself. Besides, I made the mess myself. I'll clean it up!" Allen blinked and looked at her. Sebastian had said he was ill? He opened his mouth to tell her he was fine, but she noticed and stopped him.

"Please! Don't speak! It'll only hurt you!" Allen blinked again. He touched his throat, only to find a piece of cloth wrapped around it. Now he noticed it burned. Clearing his throat also hurt. He quickly retracted his hand and looked up at the woman. Her concerned face was endearing. Allen found himself feeling a little warm. It was nice to see someone worrying about him, even if they didn't know of his Innocence, or of him being a Noah.

He stood up, smiling widely like a little boy. He knew he was being silly, but he couldn't help feeling giddy. The woman smiled back, but also looked confused. Together, though with the woman protesting his help, they pushed the cart back on its wheels. The woman laid the pieces on it, while Allen stared at the cake. It looked like a chocolate flavoured one. His stomach growled. The woman giggled and he smiled with a blush. He hadn't eaten since before he had fought the demon. His Innocence had leeched all his energy.

"Maylene, I thought I told you to stay away from the guest." Both their smiles slipped of their faces. The woman, who had now been dubbed Maylene, looked caught. "I know this is only your second day, but I should not have to tell you your orders twice." Maylene looked chastised, and she was apologizing profusely. Allen wasn't listening, though. He knew the man wasn't dead, as he was still able to hear his melody, but he didn't expect him to look so healthy! He had honestly thought the man to be dying from the poison of the demon and the large wound he had gotten.

First the melody, now immune to demon poison? He really couldn't be human.

He vaguely noticed himself being led away by the butler and the maid promising to bring him cake. He only had eye for the black-haired man, trying to find even one black pentacle on the man's skin. He didn't find one. It didn't help that the only skin in sight was his face. But Allen was sure there had been a pentacle on the man's face. Had he completely healed?

If Sebastian knew of him staring at his face, he didn't show it.

They stopped at a closed door, Sebastian knocking. He waited a few seconds, before opening the door and letting Allen enter. The Exorcist immediately recognized the room as the one he had entered without permission. It was clean and looked like it was before. Even the blood he was sure that had been spilled was gone.

"I have brought you our guest, Young Master," Sebastian spoke from behind Allen. The young boy sitting behind the large bureau looked up from a letter. He gestured for Allen to sit down and the Exorcist did so. He shifted nervously in the comfortable chair, while the butler poured some tea. The boy studied him with a hard blue eye.

"As you probably already know, I am Ciel Phantomhive, head of the Funtom Company. Sebastian tells me your name is Allen." Allen nodded slowly. The boy intertwined the fingers of his hands and leaned forward.

"Sebastian also says you hunt demons." A nod again. "I assume that was one of them." Allen started to wonder if this was going to be an interrogation, but he just nodded. Ciel was silent. Then, he reached into one of the drawers and pulled something out. He slid it forward to the Exorcist. Allen picked it up, refusing to smile. His rose cross was still in a perfect state. They had been careful with it. Perhaps Sebastian knew the value of it?

He carefully attached it to his chest, back to the place it belonged. Then, he picked up the paper it had laid on and unfolded it. His eyes widened. The picture slipped from his hands onto his lap.

"As you can see, we need your help. You seem to be the only one who knows how to defeat these monsters." But Allen wasn't listening. His hands were trembling. His mind was whirling.

This wasn't possible. He had been so sure. That maid was supposed to be the last one. The last the Earl had created. The records in the Ark had confirmed that. The Earl was dead and so were the Noah. They could not have created more demons. And yet, that picture showed a level one demon. One he was sure he hadn't saved yet, as the picture couldn't be older than one day.

He had last checked for the Screech two days ago, when he had tracked the demon in this manor. Then, he had only been able to hear her. There had been no other notes. No other evidence that there could be another demon. Allen closed his eyes, listening for the existence of a demon. He did not hear anything close to the Screech, but that could not mean anything. As usual, his hearing was limited after using his Innocence.

Ever since the Exorcists had won the fight against the Millennium Earl and the Noah, he had been having problems with his two forms. Allen had found out that having his Innocence and Noah self in one body was stressing. Every time he used his two gifts, they would clash and cause his body seizures. The one two nights ago had been the worst. He had not expected that, as he thought his Innocence would leave him after the last demon was destroyed. Like there could be no light without the dark.

Allen stared at his left hand. His Innocence had not left him. If his theory was true, then that meant there was still a purpose for the Innocence. There could still be a demon around. And a creator.

"Allen." A hand touched his shoulder. He opened his eyes to find Sebastian and his master staring at him. Sebastian stood back and Ciel tilted his head. Allen shook his head. He had been in his thoughts again. Perhaps he had stayed away from the humans for too long. He didn't even know how to listen to other people anymore. He sighed.

Ciel leaned back. He seemed to think of something, before deciding to drop it.

"This demon," he spoke it with an uncertain tone, "killed three men and two women, before exploding in what witnesses call a 'dark light'. It is however not the only one. Two more incidents like these have happened in the last week. We would like for you to tell us how to destroy them. I am prepared to pay you for this deed." Allen stared at the boy. He wanted to kill the demons by himself? That could not happen. He would die.

He shook his head feverishly, trying to tell him it was dangerous, but his throat wouldn't work. It only made him cough and feel more helpless. Sebastian came to the rescue and handed him a piece of paper and a pencil. Allen smiled at him and went to write.

This should not be possible. She was supposed to be the last.

Ciel glanced at the paper and looked up in confusion. "What are you talking about?" he demanded.

Demons were the soldiers of a man trying to conquer the world, he lied. They are not born, but created. Exorcists like me fought the demons and killed that man. All those with the knowledge to create demons are dead. I have been hunting the demons for years and I am sure your maid was the last one.

"Could not one of these creators have escaped and made new demons?" the butler inquired. Allen shook his head.

I saw them dead myself. The means of creating a demon has been destroyed and I destroyed all records on it. That wasn't exactly true, as he had only destroyed all scrolls on the ritual of creating a demon. Besides that, Allen was pretty sure no one but him could enter the Ark now.

"We are still dealing with these creatures, so that means there is someone able to create them," Ciel spoke. "For now, it is important for us to know how to get rid of this demons before they harm more people."

Demons can only be killed by a substance called 'Innocence'. You saw me use it. The Innocence in my arm is the only one left in this world.

The two stared at him. Ciel sighed.

"I had a feeling you would say that." He slid another piece of paper to him. Allen glanced at it. It was a contract. "I would like to hire you to destroy these demons, while we look for the creator. In the meantime you can help our new employees around the house."

Not ten minutes later, Allen was back at his room, watching the rain fall and eating a piece of cake. Ciel and Sebastian were still in the noble's office, the demon butler pouring his master a cup of tea. He placed it on the table, while Ciel ate a perfectly made blueberry cake.

"Are you completely sure about this, Young Master?" the butler asked. The young boy glanced at him and continued scowling at his spoon.

"He called himself 'Master' in front of that 'demon'. If he really is responsible for these monsters, it is better to have him close so I can monitor him. And if not, he still knows how to destroy them. These demons hardly sound like you, but they are dangerous." Sebastian smirked and pulled the glove of his unmarked hand off.

"A demon hunter in the house of a demon butler. How ironic."

There were black pentacles on his skin.

A/N: The difference between D. Gray-man's demons and those of Kuroshitsuji amuses me greatly, while I try to find some way to put it into the story.

I'm not really content with this story, I feel like I rushed the end. On the other hand, it sorta fits. I haven't written in a long time, so I forgot what a slow writer I am... bleh

I'm considering making this a multi-chaptered story. If enough of you want me to continue, I might. Maybe a shots, or a full blown out story. If you do, I'd love to hear what you would have in mind for this. But for now consider this complete.

I would appreciate it if you would tell me if you find any annoying spelling errors. And... Please tell me what you think! This is, after all, my first story on FF.