Aus_Snow said:
the fact that Asmodeus may or may not be one of the progenitors of the multiverse, if I'm remembering my 2e lore correctly.
2e 'Guide to Hell' claimed he was a primal LN being corrupted by evil, and spawned the Baatezu as a side effect of his fall. That book largely danced around the entire idea of the Ancient Baatorians.
Other 2e sources had the Baatezu (and Tanar'ri) as the side effects of the yugoloth/Baernaloth creation mythos, who displaced the Ancient Baatorians after being driven/herded into Baator. The Lords of the 9 don't appear till after this sequence of events, and the ultimate origin of any of the Lot9 including Asmo is left intentionally a mystery though with several potential origin natures for them given.
3.5 danced between giving the GtH idea as a rumor and ignoring entirely. The Fiendish Codex I confirmed the Baernaloth creation mythos, or rather a twist of it, as being accurate. It stated that the Baern/loths created the Obyriths and Ancient Baatorians; presumably the legend was remolded for political purposes in later periods. This opens up to potential to use both the Baernaloth creation mythos and the GtH stuff as well with only a little jostling of stuff.
But I don't have a clue how the authors of FC:II will approach the topic. Personally I'm hoping there's more mystery than any attempt at presenting a hard truth like GtH attempted to do, though sprinkling enough allusions to relevant material from various Planescape sources, maybe GtH, and new material.