About Interchangeable Demon/Devil encounters
Whizbang Dustyboots said:
...hopefully encountering one won't be interchangeable with an encounter with the other kind...
There is another (IMO better) way to ensure that those encounters are not interchangeable - put a usage note in the MM about the two monsters, and lay out different roles for the two. What's more, place Demons and Devils into different niches.
To use the monster categories I saw once in a Design and Development column, Devil should basically be assigned as Masterminds. Therefore, they should be individually more powerful than the corresponding Demon, but should also be much more likely to be encountered alone. By contrast, the Demons basically fit in the Brute category.
Amongst the changes, remove the ability to summon help from Devil write-ups. However, you conversely give them a number of powers/feats that allow them to work better with minions - perhaps an Improved Flank feat, or Aura powers similar to those of the Dragon Shaman. And definately give them a number of non-combat abilities to attract and control minions in the mortal sphere.
Demons, by contrast, are an undisciplined mob, and so have no such ability to coordinate their actions.
As a result of this, and in 3e terms, perhaps an appropriate encounter for a 20th level party would be either a CR 22 Pit Fiend
or a CR 18 Balor and his retinue of half a dozen Glabrezu demons.
In addition, you note that the two categories of creatures have different campaign roles - 90% of the time, an encounter with demons is just an encounter with demons; they've probably been summoned by an infernalist to do his evil bidding. By contrast, if you encounter a Devil, it's either because you've just fought your way through several waves of his cultists/minions, or because he's working for some higher devil in a deeper infernal plot... or most likely both.
Now, tell me that those two are not completely different in flavour and usage. And I didn't negate hundreds of pages of published lore to do it, either.
