I don't own Percy Jackson or Blue Exorcist
A small boy sat huddled in a corner, hugging his knees close to his chest. Tears streamed down his cheeks as he watched helplessly as Smelly Gabe slapped his mother around. Percy watched as Gabe punched Sally. He looked away, but heard bone and cartilage break as she fell back into the apartment's peeling walls. Gabe grinned, satisfied. Turning to Percy, he watched with amusement as the boy shied away from him, making himself smaller in the corner. Gabe approached him slowly, but a hand's tight grip on his grease-stained shirt made him stop.
Sally Jackson glowered at him, blue eyes defiant and full of fire, despite the blood that poured profusely from her nose. "You can hit me as much as you want Gabe, but don't you dare touch my son, "her words were as cold as ice. Looking at Percy, her expression grew softer and she mouthed one word to him. 'Run'. Percy looked at her with pleading green eyes, but she shook her head. Gabe raised an eyebrow at the exchange. Sally lunged forward and tried to push Gabe into a wall, wanting to buy her son some time to escape. Tears sprung up in Percy's eyes and he stood up and sprinted to the door. Throwing it open, he cast one last glance at his mother before turning on his heel and running. Gabe stumbled and watched Percy rush out with cold eyes. At first he let out an angry growl, but it quickly morphed into a sadistic grin that spread across his ugly features. Reaching into his pocket, he withdrew a lighter. Before Sally could move away, he yanked on her hair, eliciting a muffled scream. Flicking open the lighter cap, his eyes twinkled with sick amusement as a small flame sprung up.
Percy stood outside, shivering. The icy wind chilled him to the bone, and each tear froze on his cheeks. A loud shriek came from one of the apartments and within in minutes it went up in flames. He watched with wide eyes as the fire spread throughout the building. Within minutes firefighters and reporters appeared at the scene. The firefighters extinguished the flames and made a statement to the press, saying there were no survivors. Percy turned away from the scene and ran. He ran to who knows where, his small legs carrying him as far as they could. After running for what felt like hours, his legs gave out and he collapsed face-first into the snow. Curling into a ball, he tried to conserve as much warmth as he could in his hoodie. Trying to push away thoughts of his mother, he cried himself to sleep.
Later on, a tall, pale man wandered through the streets of New York City. His skin was so pale, it was almost white, and he had ebony black hair that contrasted greatly with his skin tone. He had eyes that appeared to be soulless black pits and he was well dressed in a black suit with a white dress shirt. His tie appeared to be moving, with what appeared to be numerous face swirling around, morphed in pain.
The god Hades had come to New York after feeling hundreds of souls screaming in agony. Things often happened in the city, but normally this many weren't taken in a fire. The site was a few blocks away, and by now, most of the mortals would have left the scene, allowing him to investigate the scene. On his walk, he stopped suddenly as he felt another soul's pain, except this one was still alive. Traveling down the adjacent alleyway, he found a raven haired boy, curled up in the snow. Picking the boy up, he shadow traveled back to the Underworld. The site could wait.
Percy's eyes fluttered open as he sat up in bed. Blinking rapidly, his eyes adjusted to the dimness of the room. Beside him lay a glass of water on a bedside table made of dark wood. The walls were obsidian-colored and judging by the way it looked it the torch light, it was safe to say that it was actually carved from the volcanic rock. Looking down, he realized that he had been changed out of his frayed jeans and hoodie, into a warm forest green turtleneck and jeans. He was no longer cold, but thinking about the day's events made his stomach churn.
"I see you are awake," a voice called out. In the doorway stood a man with pale skin and eyes that matched the walls. Percy jumped up startled, and backed away, hitting his head on the headboard. Percy groaned in pain. "Now, now child, I won't hurt you. My name is Hades. What is yours?"
"Percy."
"Percy", the man repeated. "Well..Who did that to you?" He pointed at the purple bruise on Percy's cheek. Percy touched it gingerly, a dark glint appearing in his eyes. "Smelly Gabe. He hurt my mommy and me." The cup of water on the bedside table shook rapidly, before shattering.
Hades eyes darkened. "He hit you and your mother?" He asked, glancing at the broken glass.
Percy swallowed the lump in his throat and nodded. "They're both dead."
"I will make sure this Smelly Gabe pays for that in the Fields of Punishment. I'm sure Alecto has grown quite bored over the past few centuries," he mused. Turning serious once again, he faces Percy. "I will make sure your mother receives a fair trial when she faces judgment." Percy wasn't sure what that meant, but thanked him regardless. "Do you know of the Greek Gods, Percy?" Percy nodded, which took as his cue to continue. "Is Gabe your real father?" Percy shook his head. "Well Percy, I am almost a hundred percent positive that your father is a Greek God. Poseidon to be exact. Do you see that glass? You controlled the water in the glass causing it to shatter."
Percy's mind processed the information, but only one thing mattered. "Why didn't he help my mommy and me then?"
Hades shook his head sadly. " I don't know. While there are Ancient Laws, I thought that he could have last interfered to help you and your mother in someway. But, if you'd like I'd be able to adopt you. After all, you are my nephew." The god of the Underworld felt for the boy, and found himself caught up in those sad green eyes. He vowed to make the boy a great so he could protect himself. He would also like company in the months when Persephone was gone. It'd be nice to have a child around, with his other two locked up in that dreadful casino.
Percy surprised the god by leaping off the bed and pulling him into a crushing embrace. He clung to the god, and Hades allowed the corners of his mouth to tug up slightly. Placing a hand on Percy's head, it glowed black for a moment. A black aura flickered around Percy's body for a moment. It disappeared a moment later. Percy's sea-green eyes had turned a shade darker and a dark ring of black had formed around his iris. "Thank you." Percy murmured.
The dreams started out small. Brief glimpses of blue flames, strange creatures different from those in the Underworld, a throne, a dark sky, and glimpses of a forked tail. They were strange odd, and Percy had no idea what to make of them. Percy had no idea what to make of them. He had no idea if he should talk to Hades about it, or if he should keep it to himself. Thankfully the answer came in his latest found himself in a strange place. Upon further inspection, he saw that it was a throne room. A dark throne sat atop a raised platform of cold tile. It wasn't decorated and the walls were bare. He found it odd that the throne room was empty. Where was the tail he'd seen before?
Harsh blue flames sprouted up around him in a flash. A figure stepped out of them, unharmed. He was a middle-aged man with short, well-kept brown hair and blue eyes that burned with a silent fire. What interested Percy most were the pointed ears and dark blue forked tail.
"Why hello Percy," he greeted with a wave. "I have been watching you for some time. It is really a shame what happened to Sally, she was my favorite descendant, but never mind that. My name is Satan." He paused, waiting for a reaction, but Percy simply stood there and beckoned for him to continue. "You have my blood running through your veins, since your mother was a descendant of mine. I'd like to increase that amount. With your godly blood it'd make you much stronger. What do you say? You'll also get to do this." He raised a hand a blue flame sprouted up.
Percy stared at him oddly, contemplating the offer. "I guess," he said at last. "Do you know my father?"
Satan smirked. "I do, but let's keep this between us." He walked over to Percy and placed his hand over his head like Hades had months prior. The fabric of Percy's shirt rippled and a small blade emerged from it. The same happened with his wrist. One blade was black with a blood red hilt with splatters of blue blood. The other was dark blue with a white hilt.
"These are your demon blades. In your dreams I shall train you to use them."
Percy nodded. "Understood."
Six Years Later
A boy wearing a black and silver hoodie walked down the streets of San Francisco, hand in his pockets. He tried looking inconspicuous as he tailed the man in front of him. In the past six years, Percy had grown taller, but he was by no means tall. He was average height for a boy his age. Years of training with some of the world's greatest heroes had melted away his baby fat, leaving him lean and fit. Despite his disagreement with Satan the year pervious, he still retained an odd trait from him. He subconsciously tugged his hood down to cover his pointed ears.
Percy watched the man veer down an alleyway and sprinted after the escaped soul. Catching up to the man easily, he watched as the man withdrew a Celestial Bronze sword from beneath his coat. The man let out a roar and brought it down in an arc. Percy blocked the strike, hearing the familiar clang of metal on metal. Gritting his teeth, he pushed the man backwards. Bringing his blade up with practiced precision, his blade met the skin of his wrist and continued through the tendons and ligaments until the weapon met the air. The severed hand fell to the ground and Percy took advantage of the man's surprise and impaled him through the chest, sending him back to the Fields of Punishment.
Hearing some shuffling behind him and cursed and faced his foes. A few floating demons and a large one decided to grace him with their presence. Cursing Satan, he ran two fingers down his wrist and withdrew his blade. "Shibo-toketsu umiryu. The sea falls silent while death prowls. Silence my enemies and devour them." Blue flames ignited atop the blade. Shadow traveling behind the demons, his blade swung through the air as he slayed the demons. Panting lightly, he wiped some sweat from his forehead.
He shadow traveled home, only to be greeted with a slap to the face. Rubbing his cheek, he looked up and met Persephone's livid face.
"When were you going to tell me?" She screeched. "When Percy?"
"Tell you what mom?"
"Perseus," she said as a warning, anger seeping into her words. "I saw you use his flames. His flames! Satan's!"
Percy looked at his feet, shuffling them nervously. "I'm sorry mom. A little while after dad took me in, Satan visited me in my dreams. He adopted me and gave me his abilities. He explained the worlds of Gehenna and Assiah to me. A few years later I found out about his plans of opening Gehenna Gate so he could invade Assiah and bring the mortals and their realm under his control. I have to stop him, and one day I'll use these powers he gave me hinder his forces."
Persephone sighed, placing a hand on his shoulder. "I'm sorry for lashing out. It's just that...Hades..Well he cheated on me with Satan millennia ago. I despise him, and after seeing his blue flames, you reminded me of that. I'm sorry."
"It's okay," Percy said, hugging her tightly.
After breaking apart, Persephone's eyes lit up with an idea. "Percy if you'd like you could go to school. This place would teach you how to become an exorcist so you could fight Satan and his forces. What do you say?"
He squeezed her hand with a small smile. "Yes."
A/N: The translation for the Japanese is Death's frozen sea dragon. Unless google translate lied.
As of 6/30/16 this chapter has been revised and edited.