Here's a question for you all.
Has there been any instances of avatars surviving the death of their source deity? I ask because I've got a case where a homebrew deity, that earlier created an avatar of itself for some reason, has died. I'm curious as to what would happen to this avatar? What if it was on another world or plane, or somehow divinely imprisoned by another deity. Or disconnected from its creator deity? With the death of the source deity... what would happen to this avatar?
Thanks.
Also, is there any way I could get rip's take on this? I know he likes these types of questions...
Aren't there also examples where a deity (not just its avatar) is believed to have been slain by the inhabitants of one particular world/Prime Material Plane, while the deity is still alive and worshipped on other Prime Material worlds?
Somehow, Terry Pratchett's Small Gods comes to mind. While I can't think of any canonical examples (not having Rip's memory for that kind of stuff), I would add my own opinion.
I think it all depends on how the deity died. If the deity died from lack of belief, then the Avatar would die as well, since it is fuelled by the same belief. However, if the deity was somehow killed in battle, then the Avatar would survive as a much weaker version of the deity (since according to 3e Deities and Demigods, an Avatar is a portion of the original deities power split off into a separate form). I sort of see the a deity being killed in battle as just running out of power to sustain itself in the face of trauma. If a part of that power is stored safely with the Avatar rather than used for fighting, then presumably the deity survives. That Avatar will either be hunted down and slain to finish the job or it might attempt to gather back its lost power before its worshippers notice the loss and stop believing.
Actually, I'm pretty sure there are canonical examples of this happening during the Time of Troubles in the Forgotten Realms. Doesn't Myrkul's avatar still inhabit the Crown of Horns? And didn't Midnight essentially become Mystra's avatar? (Something like Morpheus ritually preparing Daniel to become his avatar in Neil Gaiman's The Sandman.)
Forgotten Realm lore isn't my forte, so I'm not 100% on this. Something similar has happened in the Abyss, though, with the Queen of Chaos killing Obox-ob, but a few of his aspects surviving, one of which eventually evolving into a new (but somewhat less powerful) version of Obox-ob.
There's also the possibility that an avatar of the Suloise deity Ranet survived Ranet's assassination by her rival Pyremius several thousand years ago, and is currently dwelling beneath the Forbidden City. That's speculation, though.
In the third module of the (2nd edition) Illithiad series, Dawn of the Overmind, there is an avatar of Maanzecorian who has survived the death of Maanzecorian.
The text of the module doesn't say much except, "A pale reflection of Maanzecorian's power remians here in this area, forming a much-weakened avatar. ... Once vanquished, the last trace of the illithid deity's presence will have vanished from the multiverse."
I totally missed that part of Dawn of the Overmind. So very cool. 
Now we know how one would go about attempting to resurrect Maanzecorian...
Tiamat is notorious for having this sort of this happen. In Krynn, Tahkisis is dead (a form of Tiamat), yet she is alive and well elsewhere. And some berks from a place called the Bloodstone lands are supposed to have killed her also... see the 2nd Edition Forgotten Realms book "Faiths and Pantheons" for details, under the sidebar "Is Tiamat dead or not?". The assumption back then was that mortal couldn't really kill gods except under very special circumstances (i.e. the Avatar crisis), and that if one did get whacked, it was only an avatar and only applied to that one Prime Material world. Only another god could kill a deity for good, and only on the god's home plane could the core essence be snuffed out. Thus, if some basher on Oerth "killed" Tiamat, she might be temporarily out for the count on Oerth, but her true Outer Planar form would be fine and well, thank you very much, and still active on Krynn, Faerun, etc... (If the fool confronted her true form on Baator, he'd be a goner under 2E rules... mortals just can't kill gods...)
Doesn't Myrkul's avatar still inhabit the Crown of Horns? And didn't Midnight essentially become Mystra's avatar?
No, it's actually what's left of Myrkul himself. As the City of Splendors boxed set notes:-
"Myrkul actually enjoys his new existence and the ability to foment dissent, chaos, and death without the strictures inherent in being one of Ao's gods; his greatest satisfaction is in disrupting the organization of the Cyric-worshipers and in destroying any worshipers of Mystra (who caused Myrkul's destruction). "
Something similar has happened in the Abyss, though, with the Queen of Chaos killing Obox-ob, but a few of his aspects surviving, one of which eventually evolving into a new (but somewhat less powerful) version of Obox-ob.
Do you recall where this was referenced, rip?
The Obox-ob reference is from the Fiendish Codex I: Hordes of the Abyss. Another aspect of Obox-ob that survived Obox-ob's original death appears in "Enemies of My Enemy" in Dungeon #149.
Note that aspects in the Savage Tide adventure path are remarkably autonomous; they have different appearances and names than their creators, in some instances; two serve as generals in Demogorgon's army. The two Obox-ob aspects are identical to their creator, however, being simply less powerful versions of Obox-ob.
Is this known for sure? I thought it was still an open question of if Takhisis was Tiamat, or if she just stole Tiamat's look.
Is this known for sure? I thought it was still an open question of if Takhisis was Tiamat, or if she just stole Tiamat's look.
One idea that I've toyed with is that the deities of Dragonlance are actually draconic deities in other worlds. Sardior might be Gilean, etc. To me, this makes Dragonlance an even more interesting (and dragon-centric) world without being blatant about it.
Is this known for sure? I thought it was still an open question of if Takhisis was Tiamat, or if she just stole Tiamat's look.
One idea that I've toyed with is that the deities of Dragonlance are actually draconic deities in other worlds. Sardior might be Gilean, etc. To me, this makes Dragonlance an even more interesting (and dragon-centric) world without being blatant about it.
Ha, that's a nice one. I don't know just how well that could end up fitting, but I love the idea of it.
Reguarding Tiamat/Takhisis, it should be remembered that the writers of the Dragonlance books did not try to make what they wrote match D&D "canon" about Tiamat or about planes such as the Abyss (where Takhisis lives according to Dragonlance, notwitstanding her Lawful Evil alignment... going strictly by the books, "the Abyss" is probably NOT the same plane as the Chaotic Evil one of the same name in core D&D/Planescape.) The Planescape writers tried to patch over the differences by stating that the Inhabitants of Krynn were just clueless about the planes, but the question of whether Takhisis "really" is Tiamat was left open. If you assume the Dragonlance books are right, then they can't be identical, unless Tiamat/Takhisis spends half her time in the Abyss for some reason (I know, it's the climate...) 
The Krynnish refer to the Lower Planes (and the Astral Plane) in general as the Abyss. The Dragonlance Monstrous Compendium said that astral dragons live in the Abyss, for example, while describing the Abyss as a place very much like the Astral Plane. In 3rd edition, the Dragonlance cosmology only recognizes three outer planes: the Abyss (evil), the Hidden Vale (neutral, also the name of Gilean's realm on the Outlands), and the Dome of Creation (good, also the name of Paladine's realm on Mount Celestia).
Perhaps not coincidentally, Krynn has three moons. Eberron has 13 moons and 13 outer planes. Oerth divides its year into 12 months and 4 festival weeks, making 16 in total - the number of outer planes it recognizes, not counting the Outlands in the center of the Wheel. I haven't figured out an obvious relationship between Toril's outer planes and its celestial phenomena, yet.
The 1st edition Manual of the Planes explicitly stated that Takhisis and Tiamat were the same, and that Tiamat just avoided telling her Krynnish followers about the Lords of the Nine who dominated the Nine Hells, where she lived. Planescape left things more open.
I don't know for sure, but I'm guessing one of these three options:
1) dies at the same instant the source diety dies.
2) after the source diety dies, it has no font of power and slowly "starves" to death. In this situation, it might try to extend its life by getting people to worship it directly/ eat souls.
3)The avatar begins to lose all of its powers, and eventually becomes a mortal who vaugly remembers that he was once a being of great power.