According to Viv... the demons of the Ars Goetia were Lucifer's creations.
Some of us lore nerds have already come up with ways to step around this, such as that this is merely a cover-up by Heaven in order to hide that so many angels once fell. But what is your lore for them?
I'm canon divergent on this one - surprise surprise. I think that the concept of 'creation' is used quite loosely - as most demons are either fallen angels, powerful sinners or, (at least in viv's works), spawn of other demons.
so! the ARS GOETIA, in hh/hb continuity, are a powerful, high-ranking class of demonic aristocracy - ancient and self-perpetuating; they have hereditary titles and their bloodlines are obsessively preserved. paimon, for instance, is notoriously strict about lineage: marriage is political and dynastic, a tool to preserve the purity of the goetia line. so belonging is inherited, not earned or bought in.
their origin lies with the FALL. they descend from fallen angels - paimon being one of them - elevated as lucifer's nobility.
in short, I would interpret the concept of being 'created by lucifer' more as a rebrand (like a king making knights): when they fell to follow him, he made them into his royal court, and they were reborn into a new role and purpose - so yes, in that sense lucifer may well be the architect and curator of this part of hell's social structure.
as for the cover-up theory, for me it works if the heaven we see is a simulation where relatively young souls (or at least not old enough to remember the fall) reside, curated to maintain a fragile order and prevent any further rebellion; or if indeed the eldest angels have kept it a strict secret (for good reason): after all, if the residents learned that more than one angel had exercised free will and survived, it would shatter the illusion that angels are morally infallible. so, better to believe that lucifer fell alone because he was flawed, and that he was responsible for creating the ars goetia, than that a lot of angels followed him willingly.
