“Assist me in understanding, you are a spirit or demon of some variety, come forth to deliver unto me the mantle of saviour of mankind. Is this correct?”
The demon smiled at the good doctor patiently in the manner of one who often must deal with those with only moderate understanding of the world. The doctor did not approve, knowing himself one of the foremost physicians of his day.
“Louis, may I first say that I protest the phrase ‘Spirit’ or ‘Demon,” the creature’s overlong fingers flicked casually through the air, bracketing each word as if to separate them from the creature further, “I am a god, small and humble as I may be compared to the almighty.”
“Hrumph,” grunted the doctor, refilling his pipe, “So you have said, but I find such a claim hard to believe. Do not believe for one second the commoners belief that a man of science cannot be a man of faith.”
“Oh, I would not, Louis, I would not. No, your faith is clear to my eyes, hence my finding you, rather than the score of other doctors with a reputation approaching yours.”
“Hrumph,” grunted the doctor once again as he leaned back in his chair. He took a puff on his pipe and observed the creature most carefully. It stood taller than any of the men that Reynolds had ever known, yet sat in the high backed leather chair with no signs of discomfort. Its immaculate suit, a sombre dark grey in colour yet well cut, was exquisitely tailored to ensure the creature’s long tail had room to escape the trappings of trousers. This very tail was currently wrapped with remarkable dexterity around a cup of tea. The creature sipped the tea gently as it spoke anew, “No, doctor, you have nothing to fear from me. Your soul is safe, I am not interested in such trivialities. Souls are a matter for priests and the confession booth and, as such, I have little time for them, “the creature took another sip, “No, I am here to put forwards a proposition that would se us both advance through our various ranks; you as a doctor of medicine and I within my own purview.”
The doctor raised one eyebrow and gave a short laugh, “And now we get to the crux of the matter! You offer me a chance to succeed in the medical field, but no doubt your  promotion would cost me, no, my species dearly in the long term! I am no stranger to the works of Goethe, I have read the tale of Faust and the pacts by which he was punished!”
The creature sighed, “Once more, Louis, I am not a demon. Your soul is safe from me. I give you my word,” and the creature placed one extended hand across his heart, “At least hear me out.”
The doctor cast his gaze into the creatures eyes and slowly nodded, “Very well, ‘god’, present your proposal and I will listen.”
The creature smiled, an unpleasant thing filled with a great number of teeth that appeared too long, too sharp, “Thank you, Louis.” It took another sip, “I have been following your research with great interest and it is this research I wished to talk to you about. Your theory of Anarchic Cell Multiplication, you are almost done, are you not?”
“Indeed, I have but to place the manuscript in the hands of the publishers and I believe we can save perhaps hundreds of lives a year.”
“As I understand it, the concept of pacifying these anarchic cells is by a process of polarised light, correct?”
The doctor looked at the creature, unsettled, “How you know this I am not certain, not even my closest colleagues know this as yet.”
“Not even Jean? After all, wasn’t he the first to have contracted this failure of the body?”
The doctor puffed on his pipe. It had been true. Jean had been the boy in charge of realigning the mirrors when the doctor had been working in the field of light that was invisible to the naked eye. The doctor could still remember in horror the lumps that appeared on the boys skin, the dark swellings, the screams of pain as the twisted flesh ate away at what was still true.
The doctor shook his head, “No, not even Jean.”
“Although you have hence cured him. His body had begun to turn and you managed to heal him with nothing more than some focused light that cannot even be seen. Marvellous!”
The doctor simply nodded. He had worked frantically on the cure. Guilt - guilt and horror – driving him to repair the screaming child’s flesh. If he closed his eyes he could still see the blemishes and the worse things that lay beneath them.
The creature leant forwards, “And here we come to the crux of the matter, as it were. I want that research.”
The doctor sat up in his chair, startled, “What?! Preposterous! I would never give away…” and cut off as the creature raised one hand in a calming motion.
“My dear Louis. In a matter of only a few years, there shall be a war to end all wars,” now the creature leant forwards, its strange features appearing daemonic in the flickering firelight, “You have no comprehension, Louis, none whatsoever of the scale of this conflict.” The creature turned its head to look deep into the fireplace, “There will not be hundreds dying in this war, Louis, there will be millions. Fathers, sons, brothers, none will be spared. Children barely needing to shave will be slaughtered in their thousands. In your homeland, the living will be outnumbered by the dead. There will be no mercy, no respite. And in the end, when all the soldiers have died and nations, entire nations, lay panting and ruined, then shall come the truest killer of all.
“There will be a disease, Louis. You claim to be a learned man, so you must have known of the plagues that almost depopulated the planet mere centuries ago?” The creature looked up from the fire to meet the doctors eyes. It’s eyes burned with the truth.
The doctor nodded, shaking slightly, “I have read of the black plague.”
“This shall be as those plagues tenfold.”
The doctor sat in silence for a moment, “Creature… you are talking about the end of the species. The death of the human race.”
The creature nodded, “Or near enough. Certainly, enough would survive to rebuild the population, but perhaps only one man in ten. But this is my proposal. Your research for mine.”
“Your research?”
Another nod, “Indeed. I have spent the last decade studying this disease with the same fervour that you have researched yours. I am convinced  that my studies would allow its bearer to overcome this disease. No, it could not be eradicated, but far more would survive,” the sombre look on the creatures face disappeared to be replaced with a cheery laugh, “After all, you have suggested your notes would save hundreds of lives a year? Mine would save millions.”
The doctor pondered, “Yet, in spite of everything you have said, I feel there is more you are not telling me. Why do you make this offer, to me of all people?”
The creature smiled, “Dearest Louis, you are unique. Only you have the background in light and the spectrum to allow you to discover your cure. But, I assure you, none have the ability to rediscover my studies, not in time.”
The doctor leant back in his chair, “May I think about this, creature? You are placing in my hands a great responsibility. You suppress the details of an uncommon, near unheard of, disease and I am humanity’s saviour.”
The creature stood, “Given a choice like that, I feel I know what I would choose.” From the depths of its dark jacket, the creature pulled out a sheaf of papers, “You will be a legend, a hero. Your name will be remembered for all time.”
The doctor sighed and held out a hand. The creature carefully handed the papers over, “And you will remember nothing of your old research, I assure you.”
Nodding slightly, the creature made to leave though the study door. The doctor, looked up, unable to bring to mind any details of his previous work, “Wait, creature, I must have satisfaction. If you are a god, what are you the god of?”
The creature smiled.
“Cancer, Doctor Pasteur, Cancer”