User blog comment:Princepurple/Some Questions/@comment-26271908-20160602194756/@comment-26271908-20160603164426

By "corruption", I mean the corruption of the soul. In the moment they died, their very souls became demons. This is corruption. And, as far as we know, the oldest demons didn't suffered in Hell in order to become demons themselves. The White-Eyed Demons, as the eldest, didn't spent thousands of years down there to become demons. Lucifer created them out of his power. It took time? Sure. But I would say it were days, or even hours. The other demons were created by torture because the Demons that Lucifer created didn't had this power, so they were forced to perform the corruption by alternative means

Yes, with Amara, I totally agree. The first time, the Rabids were seemingly reflexive due to her releasing, and in the second time, it was just another random transformation, with no specific intention. She probably didn't care about what monster would appear from it, only that it would generate a monster

About the forms: Yes, the Demonic smoke is like a miniature version of the Darkness. However, this isn't an actual proof that the Darkness is related to them, excluding the Knights of Hell direct connection to her, of course. Angels treat Demons like abominations, so it would make sense if they didn't want to create any more of them. However, I think it would most likely fall under what an Archangel can do, not a simple Angel

Crowley's smoke is a joke. No explanation and no reason. Just for fandom. A stupid, ridiculous joke. It's possible that Lucifer created the Demons using the Darkness as a channeling force? Yes, of course it's possible. It would make sense and would not be a big issue. However, I particularly believed that the Mark only played a role in created Cain and the other Knights of Hell that followed him, and that the Darkness only has a similar form to the Demons because it's the form closest to pure dark, in the case, black smoke (However, something to be noted is that, when Amara and Dean met the first time inside the Darkness expanding, the interior was dark purple instead of black, though this could've been because the sunlight penetrated the black smoke and cleared the color)