Does Divine Word’s Killing Effect Come Before or After the Banishing Effect (For Fiends)

This question is stated right in the title.

In this case, a cleric might cast Divine Word with a fiend with 20 or less HP in the area, and the fiend can hear the cleric.

As we all know, if a fiend fails its save against Divine Word is banished to its home plane. However, all creatures with 20 HP or less is killed instantly. Would, say, a demon that failed its save while under 20 HP be killed first, or sent to the Abyss, then killed there? Same thing with devils, night hags, rakshasas, yugoloths, et cetera. The yugoloth home plane is Gehenna, for specifics.

Do fiends need to sleep?

Monster Manual states that undead and constructs does not need to sleep.

But it is unclear if fiends need to sleep. What should they do to make a long rest?

There are fiendish abilities with "restore till short or long rest", that’s why they definitely should rest in some kind.

What is the in-universe explanation for why succubi, who were demons, became “neutral evil fiends” in 5e?

The Forgotten Realms wiki page on succubi tell us (specifically in footnote 1) that in 1e, 2e and 3.Xe1, succubi were chaotic evil demons, but then were retconned to be lawful evil2 devils in 4e and have now just been made into generic neutral evil "fiends" in 5e, presumably in an attempt to avoid contradicting any previous editions’ lore.

Does 5e give any sort of in-universe lore explanation as to why they are now neither devil nor demon? The 5e Monster Manual entry doesn’t really explain that besides briefly mentioning that they "can be found in service to devils, demons, night hags, rakshasas and yugoloths", again presumably to avoid contradicting any previous editions’ lore, but without explaining why this is now the case.

This is the second part, which was split out from another question; see: What is the in-universe explanation for why succubi, who were demons, became devils?


1 Actually, the footnote on the Forgotten Realms wiki page only says 3e, but I know it was still true in 3.5e because of Neverwinter Nights 2, which was a video game based on 3.5e. In this game they were considered demons, which is incidentally my introduction to D&D and why I consider succubi being demons to be what they "should" be.

2 I say "lawful evil", because that’s what a devil’s alignment is, but I’m aware that 4e changed the alignment system, so it might not be so accurate to claim they were "lawful evil" in 4e, but at the very least, in the context of D&D overall, they would have been considered lawful evil all the time they were considered to be devils.

What is the in-universe explanation for why succubi, who were demons, became devils, then became “neutral evil fiends”?

The Forgotten Realms wiki page on succubi tell us (specifically in footnote 1) that in 1e, 2e and 3.Xe1, succubi were chaotic evil demons, but then were retconned to be lawful evil2 devils in 4e and have now just been made into generic neutral evil "fiends" in 5e, presumably in an attempt to avoid contradicting any previous editions’ lore.

Unlike with the Shadar-kai, I believe there was supposed to be some kind of canonical in-universe lore reason as to why these demons became devils. What was that reason? I assume it appears in some 4e material somewhere? I’m only really familiar with 5e material…

Furthermore, does 5e give any sort of in-universe lore explanation as to why they are now neither devil nor demon? The 5e Monster Manual entry doesn’t really explain that besides briefly mentioning that they "can be found in service to devils, demons, night hags, rakshasas and yugoloths", again presumably to avoid contradicting any previous editions’ lore, but without explaining why this is now the case.


1 Actually, the footnote on the Forgotten Realms wiki page only says 3e, but I know it was still true in 3.5e because of Neverwinter Nights 2, which was a video game based on 3.5e. In this game they were considered demons, which is incidentally my introduction to D&D and why I consider succubi being demons to be what they "should" be.

2 I say "lawful evil", because that’s what a devil’s alignment is, but I’m aware that 4e changed the alignment system, so it might not be so accurate to claim they were "lawful evil" in 4e, but at the very least, in the context of D&D overall, they would have been considered lawful evil all the time they were considered to be devils.

Is there any lore to suggest fey or celestials can only be killed on their home planes similar to fiends?

This answer to a different question (about D&D 5e) says:

To open, lets look at a sample of the rules that say you cannot permanently kill such a creature outside of their home plane…

The only way to truly destroy a demon is to seek it in the Abyss and kill it there.

MM 51

Devils that die in the Nine Hells are destroyed forever

MM 67

Only on its native plane can a yugoloth be destroyed permanently

MM 311

Of note: Angels in the 5E MM do NOT have this protection. Weird as it may seem, it is actually easier to kill a Celestial than it is to kill a Fiend.

So, going by the lore available in 5e, celestials can be killed permanently on any plane. Obviously this quote doesn’t mention fey, but I think of celestial, fiends and fey as being grouped together due to certain spells in 5e, such as find familiar or find steed, saying that the spirit can be one of those three.

Anyway, my question is, even though the lore stating that fiends (specifically devils, demons and yugoloths) cannot be killed outside their native planes is well established, is there any lore from any edition of D&D that suggests that the same rules exist for celestials and fey?

Which (if any) fiends die of old age?

I’ve seen people say that fiends can live forever, but never a source for where this fact is from or when/why it’s the case. At least in 3.5e various things refer to creatures’ “time being up” without mention of exceptions, but is there any reference in any version of the game that points one way or the other for extraplanar/native demons/devils?