Woah woah woah. If the aura that we know as Dark's existed before him and isn't actually *from* him, then... Where did it come from???
I don’t think of it as existing before him, only that it existed inside him without him knowing it. It’s his darkness, but he didn’t know that he could tap into it before. Then, when he got to his lowest point, the darkness took control, and Dark let it. Only after that initial possession did Dark take hold of the darkness and use it for his own devices.