But, I have zero problem with demon worshipping orcs. I remember when orcs were CE, so, supreme destruction orcs don't bother me in the least. Heck, gnolls that venerate some god works for me as well. Scarred Lands, for example, doesn't have Yeenoghu, AFAIK, and gnolls would venerate Vangal the destroyer, by and large. Then again, is Yeenoghu a demon or a god? Well, he's appeared in the Dieties and Demigods at one point, so, you can make the argument either way.
I guess that's the other reason why flavour text is so unimportant to me. It's been contradicted and rewritten so many times across editions, you can make a decent argument for anything. Heck, gnolls in Basic/Expert, where I started D&D, there were no demon lords. But, it did have gnolls and orcs. Does that mean that I wasn't playing the story of D&D when I was playing Moldvay Basic? Of course not. So, if I can play two different flavours of D&D which share virtually no flavour ties at all, why would I find it necessary to include a particular edition's flavour in my home brew game?
You know the game. You know the monsters and the tropes. So any changes you make are informed changes, based on the presentation of the monster as it's been (or as you've perceived it) over the years: you know both orcs and gnolls are the same alignment and thus feel comfortable swapping their religious inclinations. That's your choice.
But having the flavour allows you to make that choice. You could also choose that the flavour is just fine as it is. Perhaps gnolls just don't interest you, so you don't see the need to make any changes. The presence of the flavour makes things easier. Not having the flavour would make those races much more generic, much harder to tell apart. The flavour differentiates them as the low CR humanoid monsters.
But monsters are a complex example.
An easier one is something like, oh,
fireball. The description in Basic says:
A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of flame. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 fire damage on a failed save, or half as much damage on a successful one.
The fire spreads around corners. It ignites flammable objects in the area that aren’t being worn or carried.
What's flavour and what's mechanics in that? One would argue that the only mechanics are:
Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 fire damage on a failed save, or half as much damage on a successful one. That'd be the part singled out for a Hit/Miss line in 4e, while the rest would like be in italics below the name.
But the rest of the flavour could still have a mechanical or game effect. The wizard points a finger and releases a streak of light that explodes. As I said earlier, what if someone tries to intercept? It also implies you need to be able to see the center of the explosion to aim. It also emphasises that you aim at a point, not an item. So you can detonate in mid-air.
There's also the description of the "low roar" that might call for Wisdom checks to hear the blast.
And, of course, the fire ignites things like flammable objects. If just going be "the rules" then it only affects creatures, as they're the ones called out to make saving throws. This came up a few times in 4e, when powers specified "creature" or "enemy" in the attack line, meaning they couldn't be used to, say,
ignite a library or blast down a wooden door. Not according to RAW.
