As always, answers are interesting and I enjoy reading them. Thanks!

Religious fanatics: "Dungeons and Dragons is satanistic! It's full of demons and angels!"

TSR: "Demons and angels? What demons and angels? Those are Tana'ri and Aasimon, honest!"

Religious fanatics: "You are right. That's completly different. Carry on, good citizen."
Good one!

That's exactly what Eldan said, Edreyn. Baator is an invented word, simply for the reason that "Hell" couldn't be used anymore. With "Abyss" one has a degree of seperation to the "hellish" meaning, which grants plausible denieability.
Okay, but Gehenna and Limbo are still associated with Hell. Though Gehenna is a real place, it still used as synonym for "Hell". And Limbo is a "zero layer" of Hell according to Dante, and directly described as one. City of Dis and names of Carceri layers are from same source. Why those were left then?

Draeden are like that. Some of the Elder Evils in the eponymous book are described like that, but they are overhyped. Tharizdun has an reputation like that, but... who knows?
Yes, I remember reading about them in those threads. But can a mortal become something like this? I saw the name Tharizdun before, but don't know who he is.

The Graveyard of the Gods floats in the Astral and is patroled by the Gravekeeper. Aoskar's corpse is there. As far as I know every dead deity has a corpse there.
Now that's interesting, never read about this before. I always imagined dead deities randomly floating in Astral, without any specific place, center of pattern. Where I can read more about Graveyard and Gravekeeper?

I do not see why you the skirmishes between the Gith races considere of equal importance to the Blood War, or even of greater importence than the fighting between the Gith and the illithids, or any of the other "eternal" wars like between Gruumsh and Corellon Larethian, or Gruumsh and Maglubiyet, or Thrym and Thor, or whoever.
I am writing about conflicts I know from Torment or lore books. As for illithids, I'd say that the conflict between Githyanki, Githzerai and Illithids is one war, just with three sides instead of two. I honestly don't know what is longer - war between deities you mentioned or war of both Gith races with mind flayers. I just was thinking that Blood War and the war of Gith races can be seen as something similar.

I'll update my question then: is there any additional eternal wars that aren't between deities, but between races or species? Outside of Acheron.

I don't know, but in my opinion a mirror Sigil (let's call it Rune) shouldn't exist. It infringes on the importance of Sigil as a fulcrum of the multiverse. (I mean, if there is a second Sigil, why did Vecna intruding into Sigil had those grave rammification for the multiverse?) Also, Rune's existence opens up a lot of uncomfortable questions about the Lady.
Yup. I wonder if there is or was a Lord of Pain. Maybe he offended Lady who had to flee Rune and create Sigil. Now we know why she is that angry on everyone!