This was the point of no return, if such a thing existed. It was laying right in front of him in the shape of a girl, although the body did not match the soul. There wasn't much of a soul left, in fact, though there was certainly some manner of consciousness taking root in what was more or less a corpse.
It was all extremely fascinating, this concept of demons. There were, of course, many creatures that fit that term. The doctor was quite aware of the many altverses and multiverses out there, so he had an idea of the whole spectrum. They'd certainly let a wide variety of demons into this place since its inception.
This one, though, was peculiar. The hollowed soul had once been that of a human, and perhaps some memories still remained, even if there was no real capacity to care about them. The demon even possessed a name still, which was a sign of lingering humanity on its own.
All the lore said that once a human became a demon, there was no way to go back. What they needed to know was if that was really true. Humans, after all, were the easiest to manipulate. Something that felt nothing and only looked out for itself was hardly useful at all, was it? But if they could fix that, the sheer amount of experience that Ruby had, being centuries old, would certainly be of value to the general.
And so the doctor had ordered this demon up to the exam room. As usual, there was one central light shining right down on Ruby's restrained form. The doctor, meanwhile, was standing in the corner, tapping Ruby's file against his hand as he waited for her to come to.