Archdevils through the Years

[the Jester]

The short version: What do we know about the old arch-devils who have been replaced over the years? The ones who aren't in charge anymore? Guys like Geryon, Tiamat (as mistress of Avernus), Scylla, etc.?

I'm looking for flavor information from any edition of D&D, including "the Politics of Hell" article. Even just a list of all the ex-ADs we know of would be cool.

 

[Thanael]

http://www.enworld.org/forum/general-rpg-discussion/187479-lords-nine-hells.html (BOZ info gathering thread)
Lords of the Nine Hells - Ghwiki
Reckoning of Hell - Ghwiki

 

[howandwhy99]

By the 1E DMG there were 4 Archdevils in the monster lists:
Asmodeus, 199hp, a Supra-Genius with a magical rod.
Baalzebul, 166hp, a Genus who could poison.
Dispater, 144hp, a Genius with a magical rod.
Geryon, 133hp, only Exceptionally intelligent, but he could poison and had a Horn of Minotaur Summoning (5-20).
All of them had magic use and psionics.

By the encounter tables, they could be encountered in:
An 8th - 16th+ dungeon level. (Dungeon Table X)
In Astral space.
Or as a Psionic encounter, rolled when an encounter was called for, but psionics had recently been used.
Depending on how it was determined they could even be a city/town encounter.