I think the way this spell was written, along with the power level of the spell and the 5000XP cost leads to the following interpretation:
- Vampires who are in gaseous form are not dead/destroyed, and therefore are probably unaffected. A very open interpretation would suggest they are also returned to full HP, albeit already be halfway back to their coffins at that point.
- All other dead/destroyed creatures from this battle are returned to life/unlife with full HP, no level loss, without regaining/recharging spells or other abilities that are limited use, but not losing any prepared spells or abilities, either. (This includes disrupted creatures, as disrupting an undead vampire is the same as destroying it with sunlight or
disintegrate or anything else like that.) They are prone and not carrying anything in their hands (in fact, someone could have picked up their stuff), but they are alive/undead. I'd also rule them flat-footed and reset their initiative to the end of the battle round.
That said, I would probably change this slightly, based on two factors: 1) the flavor of the death cleric's god, and more importantly, 2) how likely your PCs are to survive.
If your PCs are likely to survive the above, then I'd say run with it. The disrupting weapon(s) functions every time it hits, so they've always got a chance of destroying those vampires again. You just need to measure, very carefully, how much of a chance the PCs have to make it. If it's an ok chance or even a slightly worse than average, I'd say stick to it. Those epic spellcasters are epic for a reason.
If they don't have a very good chance at all, I'd change the ruling slightly based on the god. If the god is evil, but not necessarily necromantic, I'd rule this way:
- Vampires who are in gaseous form are not dead/destroyed, and therefore are unaffected.
- All other dead/destroyed creatures (including disrupted ones) from this battle are returned to life. This means they are returned to actual life, and lose the vampire template. (They retain their CE alignment and loyalties, and are only as old as they were when they gained the template.) They return with full HP, no level loss, without regaining/recharging spells or other abilities that are limited use, but not losing any prepared spells or abilities, either. They are prone, flat-footed, and not carrying anything in their hands, and their initiative shifts to the end of the round.
This reduces the challenge rating of these baddies and thus the encounter overall - potentially helping the players (unless literally everything they have is anti-undead, in which case it might hurt more than it helped). Plus, it's ironicly funny, and the sort of mean-spirited thing an evil god might do.
If your players STILL don't have a snowball's chance of surviving, and/or the evil god is somewhat necromantic or particularly CE, then I'd tip the scales one further:
- Vampires who are in gaseous form are not dead/destroyed, and therefore are unaffected.
- All other dead/destroyed creatures (including disrupted ones) from this battle are returned to undeath. This means they are returned as zombies, gaining the zombie template and losing any other template. They return with full HP (for zombies), no level loss, without regaining/recharging spells or other abilities that are limited use, but at the same time they'll lose all spell usage because of the zombie template. They are prone, flat-footed, and not carrying anything in their hands, and their initiative shifts to the end of the round.
This is particularly helpful because the zombies won't pose nearly as much of a threat as the vampires, the party's anti-undead equipment will still work, and the main threat - the epic spellcaster - is still effectively out of the battle. It's also something a particularly CE god might do to someone who bothered to ask him to help win a battle for them.
These are just three options - there are always more. However, I believe the main points of your original interpretation of the spell are correct: all the "fallen allies" are revived, and they receive full HP and no level loss or prepared spell loss. Destroyed undead (even disrupted ones) are raised (look at the description of the
resurection spell - it includes exactly this type of situation). Line of effect is irrelavent. This is how I'd rule it for an 18th level cleric burning 5000 XP, and this is how the archvillian should get it, too.