Step one prompts:
- oroboropolis was created for a purpose long ago, long since forgotten by the denizens and likely even the city itself
- oroboropolis stitches together the memories of absorbed souls as a base for its design work. Perhaps it was intended to use intentions instead of simply memories or thoughts, but it was either misdesigned or has since become corrupted. This idea doesn't just justify my last idea, but gives you an opening to create loads of differently-styled parts of the world, and an opening for some sort of magic that involves shaping parts of the city to your will, taming it, as it were (which would most likely also corrupt you, as the city starts using you as a design base in addition to as a source of ideas)
- oroboropolis was definitely first created somewhere, but it has an ability to create large spaces that are bigger on the inside, which means that we might think we've left the city only to still be inside it, and thus it might be really hard to realize if we have actually found the place where the original city was made (especially because it would have spread into there and corrupted parts of that world too).
- this I guess is a prerequisite for all the above ideas, but oroboropolis uses reality-warping powers to expand itself, but it's constrained in that the reality-warping has to make local sense, since the original design presumably intended it for the use of creatures that are generally not comfortable with warped reality. The constraints may loosen in stressful cases.