A/N: Ah Yukio and his boring rants about demon science in this chapter…


Possibly the most lethal substance in existence was the blood of Rin Okumura.

And as a doctor, and Rin's brother… It was Yukio's sole responsibility to handle the sample with caution. Slowly, the teen poured the blood from a flask and into a large beaker. He observed the material carefully. There appeared to be no separation of red blood cells and plasma, a good sign. However, there had been cases where the victims would catch the virus early and, at first glance, their blood appeared normal. Due to this, Yukio needed to perform more intricate tests on the sample.

He snuck out….I SHOULD have known he was going to sneak out…Now Rin might be…

The doctor swallowed back his feelings of failure and began his work. I need to focus. He took the beaker and poured roughly three drops into another glass filled with a clear liquid. This fluid was plasma taken from previous victims. The test was meant to detect traces of the virus in its early stage. If the blood turned black the moment it came into contact with the substance, the tested patient was infected. Logically, clean blood would take longer to be contaminated by the plasma. This was why the substance would remain red if not diseased.

However, as Yukio suspected, the sample of Rin's blood didn't react normal to the liquid. The moment they touched, the mixture burst into large blue flames. Startled, not expecting such a large reaction, the young doctor stumbled backwards and hit the floor.

"G-GYAAA!"

However, as the flames died down, they destroyed nearly half of Yukio's equipment.

Melted beakers and flasks covered the table. A hypothesis was born; Rin could never contract the virus. Even if the plague entered his body, his blood would burn out the virus before it took effect. The thought was sensible; Rin carried the blood of Satan, the god of Gehenna. No matter what demon caused the plague, none were powerful enough to overcome the blue flame… It felt as though pressure released from Yukio's shoulders…his big brother was clean…he was safe…

As for Rin's friend…

Fortunately the flask containing Aidyn's blood was too far to be damaged by the flames. It remained perfectly intact. However, due to the destruction of his equipment, Yukio could not perform the same test that he used on Rin's blood. Instead, he was forced to resort to a C.T.A. (Coal. Tar. Analysis.). In this, a doctor would give coal tars (the lowest form of demon) direct access to the patient's blood.

If the demons were attracted to the blood, the patient was infected. Not much was known about the virus. However, exorcists hypothesized that a coal tar's attraction to such material was due to a high concentration of water in the blood, hence, the plasma. Yukio usually preferred methods other than C.. There was a high margin for error in such tests. The coal tars were living, which meant they could react differently depending on their surroundings. A response to dampness of a room might be mistaken as a test result.

However, he had no choice in this situation. Yukio rummaged through an old wooden closet and retrieved a jar of coal tars from the far back. He placed the glass container on the stone table and opened the lid a crack. From there, Yukio drizzled Aidyn's blood down the left wall.

The following observations could be described as…..bizarre…

There was no attraction to the blood…yet…the coal tars' behavior was…. unnerving… The doctor observed as the tiny black creatures slammed into the sides of the jar, bounced off, then slammed again. Their movement became more rapid by the second. The demons clumped together and gave long, drawn out squeaks….

…However, they did not seem to be afraid…

The coal tars… appeared to be… killing… each other…

Yes, it was true-the small demons were in a state of bloodlust. Each one devoured the other, ripping off one's tail, or clawing out one's eyes…It was truly a strange reaction that Yukio had never seen before… Aidyn…the boy was certainly foreign. He was most likely a L'Écarlate, a sibling of his colleague Isaac. If so Isaac was hiding something from him. This boy, there was something strange about him…Yukio remembered feeling…an irrational sense of revulsion at the sight of the student… This and the coal tars' violent reaction was certainly suspicious... Did this boy have a demon-caused condition? Is it a new strain of the virus?

"Are you hard at work, Mr. Okumura?"

Yukio flinched. The voice held no accent…it wasn't Isaac. However it was familiar…and could have only belonged to one person. The young man whipped around to address his superior. However, he could not hide the startled expression on his face.

"S-sir!"

Arthur Auguste Angel responded to Yukio's greeting with an order.

"Sit down, Mr. Okumura."

The adolescent retrieved a chair and followed the command.

"Sir, I-"

Arthur raised his hand and Yukio ceased speaking. Sweat coated the back of the teen's neck. What was the Paladin doing here? Instantaneously, Yukio's mind jumped to the wellbeing of his brother. Does he know about Rin sneaking out…..? The doctor noticed that by sitting, he was forced to look up at his superior: the position was much more than a coincidence. Auguste placed his arms firmly behind his back and began to speak.

"I suppose you're wondering why someone of my rank traveled all the way from the Vatican to see you."

"…."

The Paladin made it sound like he took a long trip to get to Japan, meanwhile Yukio knew that he probably just used one of the exorcist keys to get here. Auguste Angel was merely a door away from this country. However, Yukio would never announce that in front of such a high-up official. A tactless statement such as 'Yeah, sure you traveled far with that key in your pocket' was something only his brother would say… Yukio had knots in his stomach… Arthur continued to speak, his voice cold, merciless, yet, condescending all at once.

"As Paladin it is my duty to carry out the orders of the Grigori."

Yukio nodded, Angel continued.

"As of this moment their attention is focused directly on the epidemic. Every exorcist from each corner of the earth, containing a doctor meister, is searching for a cure. This is far more than a regular task to them…. it is a challenge, a game of glory. Any one who succeeds will be written down as the greatest doctor in history… A rather unsettling situation…"

"Sir….I don't believe I follow…"

What is he saying…?

The Paladin turned his back to Yukio.

"Mr. Okumura, there is a very high concentration of the plague in this country, correct?"

"Y-yes…"

"Not only this country, but this area, True Cross Town. This section is the most contaminated."

"Yes sir but-"

"Hmm, well, don't you find it strange that the attention of the Vatican, and every exorcist alike is focused entirely on this one. sole. area? Shifting their prime goal –Assiah's wellbeing – to this child's play?"

Yukio dug his mind for a response equally as cold.

"Yes sir, while I admit that the intentions of certain exorcists may not be as honorable as others, isn't the virus still a threat to Assiah?"

Angel remained stern and patronizing.

"Well, if it is a distraction from Satan like I assume, then yes, it is a large threat."

"W-what?"

Yukio jolted up in his chair.

"The virus?...A distraction?"

The adolescent gasped, finally realizing what the Paladin was implying. Yukio stood from his chair.

"WAIT! The Vatican doesn't suspect Rin has anything to do with this, do they?"

Auguste whipped around in a flash. With one hand he shoved Yukio down by the left shoulder. As the doctor crashed into the chair, it collapsed beneath his sudden weight. The Paladin did not release his grip from the teen. Instead he spoke low in Yukio's ear.

"No…they don't suspect your brother, but I do…"

"….Are…are you suggesting that Rin is the cause of the virus?"

"You are correct Mr. Okumura. It is perfectly logical, the precious child of Satan providing a diversion while his father secretly plans an attack."

Yukio gritted his teeth and struggled upward, his hand twitched towards his gun. However, Angel's grip kept him down. The young doctor forced himself to remember that this was the Paladin, the most powerful exorcist…any act of aggression against him would be disastrous. What happened to having tact?

"Arg!- My brother is innocent...Besides, it was the Grigori's decision to keep Rin Okumura alive. He is suppose to take the exorcist exam in four months… They ordered us to use him as a weapon"

Auguste Angel stuck his nose up and smirked.

"Did you not hear that I have said? I told you that as of right now, the Grigori is focused entirely on the plague…In fact, the exact words that they told me was…'Destroy the virus at all costs…' "

Yukio grew silent…

"Mr. Okumura, you've begun your training at age seven…many consider you a prodigy in Demon Pharmaceuticals."

"…."

"If this is the truth then I suggest you use your knowledge to the best of your ability and find a cure…In four months…"

Angel released his grip from Yukio and the doctor slumped to the floor. Then just before the Paladin left the room he turned his head and spoke one last time.

"If not, I will direct my orders on your brother. I'll have him dragged down into a lab and have him used as a guinea-pig for a cure, understood? I suggest you keep him on a tighter leash this time. He better not run out like he did this morning."

Angel left the room, the sound of his heavy footsteps faded away into oblivion.

Meanwhile Yukio sat there on the floor…staring into space…..

The ravenous coal tars were long forgotten…