Authors Note: Helllloooo~! This is my first published fanfiction, so yeah! Please correct me if I make any mistakes, 'cause I don't have a beta. Thanks for reading!

IMPORTANT: This is an AU in which Rin is not Yukio's brother, although Yukio was still raised by Shiro Fujimoto (who's still Yukio's foster father). Therefore, he did not suffer early temptaint, and he also didn't have that protective complex concerning his brother, so he did not become an exorcist at an early age like in the manga. Rin is still the main character, though. He just doesn't show up 'till, say, next chapter.

Btw, this is completely manga-verse, with the exception of Ukobach.

~Prologue~

Yukio rubbed his eyes furiously, refusing to show tears. I have to be strong. For Father. He stared longingly at the freshly placed gravestone before a clenching feeling wrapped around his heart, and he was forced to turn away.

It had been a week ago when Yukio found his foster father, Shiro Fujimoto, collapsed on the floor of the monastery basement, clutching his heart and bleeding from practically every visible orifice. And then when Shiro was consumed with blue flames, Yukio found his dying foster father handing him, of all things, a simple flip phone. His last words were forever embedded in the teenager's mind.

"When you leave the monastery… I want you to use this… There is a single number stored in its memory… It's a number of a friend of mine… Who will protect you… from the demons…"

Yukio still didn't fully understand why he needed protection from demons, who supposedly weren't supposed to exist. But after that night, after the unnaturally cold flames devoured his father, Yukio began to wonder and doubt the existence of such creatures- which was very, very bad for a man of science such as himself to do.

Needing a distraction, Yukio swiftly glanced to check if anyone was watching nearby before whipping out the cell phone that Shiro had given him. It indeed only had one number, with no name.

Riiiing. Riiiing. Riiiing. Bip.

"A pleasure to meet you, Okumura Yukio."

Yukio looked up to see himself surrounded by a loose ring of men, dressed in long black garb, with the exception of what looked like the leader. Though his capability as a leader could probably be questioned.

The man who had spoken was tall and had a rather sinister face- dark eyes and a purplish goatee- which clashed violently with his odd taste in clothing. He was wearing a white stove-top hat, a large (also white) cape over a tailed coat, and puffy white breeches. His comical striped stockings and pointed boots only made it worse. Wielding a patched up umbrella, the man looked like something that had escaped from a torture circus.

"My name is Mephisto Pheles. I am a friend of Fujimoto's, and also, coincidentally, the chairman of the True Cross Academy, which I am aware you will be attending soon."

Yukio nodded soundlessly. He was, indeed, going to True Cross Academy that fall.

"You have my sympathies for what you went through."

Not entirely ready to trust him yet, Yukio cautiously retorted, "Instead of your condolences, I would much prefer an explanation."

A purple eyebrow shot up. "Hmm? Quick to the chase, are we?" After a long, awkward silence, he added, "I will explain everything on the way there."

"Where?"

"To True Cross Academy, of course."

Yukio really shouldn't have been surprised at the electrically pink limousine that arrived soon after, but he couldn't help wonder where the supposed chairman's sanity had gone. After his meager amount of personal possessions were loaded into the trunk, Yukio warily stepped into the absurd vehicle and looked at Mr. Pheles, expecting an explanation.

"What killed Father?"

Mephisto turned to glance at Yukio. "A demon."

Yukio was a little thrown back at the blunt reply, but stared keenly at Mephisto none the less.

"Demons exist in another world, known as Ghenna. You live in Assiah, which is the human's realm. The only means of travel between the two are for a demon to possess an object in Assiah. Different demons possess different things, and seek to destroy all forms of happiness in Assiah. The one that possessed Shiro had incredible power, and consequently, destroyed your father's body."

Yukio absorbed all of this, and tried to ignore the nagging, unreasonable feeling that made him want to punch Mephisto's deranged lights out and get out of that car as fast as possible. "But why did the demon kill Father?"

Mephisto chuckled. "Your father was an exorcist. The highest ranked, in fact. A Paladin. Exorcists make it their duty to exterminate demons. The one who killed your father did not need any other reason."

Yukio glared at the chairman. "Then, what kind of demon was it?"

"The God of Demons- Satan himself."