D&D 5E Non-spell area effects vs. total cover

[Harzel]

A recent thread concerning whether the Slow spell goes through walls / around corners got me thinking ...

As mentioned in the other thread, for spells, there is a general rule

A spell’s effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn’t included in the spell’s area. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9.

And then specific spells have explicit exceptions (usually 'spreads around corners').

Ok, but what about the numerous area effects produced by various creature abilities that are not spells? Their descriptions use language that is very similar or identical to spell area effects. Furthermore, in at least one instance - the Darkmantle's Darkness Aura - the same exceptional language ('spreads around corners') is used. So it seems to me that the obvious conclusion is that these effects obey the same general rule as spell effects.

But it's a little weird that a red dragon's breath weapon is less spread-y than a Fireball. Even weirder that a copper dragon's Slowing Breath (gas) doesn't act like Stinking Cloud. But maybe we can talk ourselves into being ok with those.

Now talk to me about a banshee's Wail.

Have I just overlooked the rule covering these? If not, how do you​ run these?

 

[Rya.Reisender]

If the monster ability refers to an Area of Effect (e.g. "Cone"), I'd apply the rules for that AoE.

 

[Coroc]

Well line of sight is a thing in 5e, so if you have none aka total cover, no spell should work on you unless it's description says otherwise. If a mob duplicates a spell I would rule the same.
The example with fireball vs. Dragon breath is not exact. Origin of the heat in case of a fireball is upfront where the center of the spell is. For the dragon it is in his mouth aka head aka might as well be its eyes so no los.

 

[TaranTheWanderer]

I just read Banshee. It's anyone within the range that can hear the wail and it doesn't require the banshee to target anyone. In my mind, that means cover doesn't help you because it doesn't provide cover from sound. A silence spell would make you immune, though.

 

[77IM]

I concur with [MENTION=15882]TaranTheWanderer[/MENTION]. The banshee's wail is not a sphere area. It simply affects the creatures that meet the criteria for being affected.

As for the dragon breath, I guess I imagine the dragon exhaling very forcefully, so the effect won't spread around corners the way it does for slower-moving effects like fireball and stinking cloud. It also makes for better game-play by encouraging players to seek total cover from the dragon's breath. But, I'd also buy the argument that the developers simply left off that "extends around corners" text for the sake of brevity and simplicity. This may be one of those areas where the DM's judgement needs to take over; for example, if the dragon breaths fire into a small stone room, the fire might curl around and fill the room even if that's outside of the area of the cone (sort of the way fireball used to fill areas by volume, except without forcing the DM to halt the game and perform multi-dimensional calculus).

 

[Harzel]

If the monster ability refers to an Area of Effect (e.g. "Cone"), I'd apply the rules for that AoE.

Sure, but that doesn't help. The rule for how a spell's effect expands (that I quoted) is separate from the rules for the individual shapes and applies to all of them.

 

[Rya.Reisender]

Sure, but that doesn't help. The rule for how a spell's effect expands (that I quoted) is separate from the rules for the individual shapes and applies to all of them.

The text you quoted is part of the Area of Effect section, so I'd apply that as well of course. That is unless the ability description says otherwise.

Banshee's Wail is very specific in how it works and doesn't even refer to an AoE type.

 

[Harzel]

I concur with @TaranTheWanderer. The banshee's wail is not a sphere area. It simply affects the creatures that meet the criteria for being affected.

I'm not sure I understand what you mean, but I'll give it a shot. I think (maybe) you are saying that the banshee's wail is not an AE (spherical or not). And your second sentence is supposed to explain why. Now, sorry for the upcoming pedantry, but really I am just trying to sort this out in a way that will allow me to reply usefully. Also, it may sound condescending; please just chalk that up to my inability to phrase it more gracefully. I appreciate you engaging in the thread; I'm not trying to insult you.

The way you have phrased that second sentence, it is a tautology, so it's not very helpful in that form. Does this rephrasing reflect your intent?

The description of Wail doesn't define a spherical entity; it just sets out a criterion for selecting the creatures affected.​

Assuming that I've at least gotten close, I think my main point in response is this: whether an effect is an AE is solely a matter of the mechanics; the fiction/fluff does not matter. In particular, for an effect to be an AE, the fiction does not need to include a physical manifestation of the shape of the area. AFAIK, the only things necessary for an effect to be an AE are a) it can affect multiple targets; and b) the criteria for valid targets includes their location; and (probably) c) the set of acceptable locations for targets forms a contiguous region, for some reasonable definition of contiguous that I don't even want to try to think about. Not that anyone would even think about that last bit unless some unholy combination of a rules lawyer and a mathematician got involved.

Anyway, to get back to the point that I am guessing is where our thinking diverges - for many AEs, the fiction does specify a physical manifestation, but that is not necessary. For example:

Fear - You project a phantasmal image of a creature's worst fears. Each creature in a 30-foot cone must succeed on a Wisdom saving throw or drop whatever it is holding and become frightened for the duration.

This is most certainly an AE spell. And "Each creature in a 30-foot cone" is a location-based criterion for the creatures affected in exactly the same way that "All creatures within 30 feet of her" is for Wail. Wail doesn't have to mention the shape of its area because spheres are so easy to describe, but "everything within 30 ft. of a point" is literally the definition of a 30 ft. radius sphere.* Note that you could define the criterion for creatures affected by Fear without mentioning the word 'cone' - it would just be a lot more complicated.

So as far as I can see Wail is certainly an AE, and it happens to be spherical. If you still want to contend that Wail is not an AE, I suggest either showing me why it does not fit my definition, or telling me why my definition is wrong.

Other comments:

As for the dragon breath, I guess I imagine the dragon exhaling very forcefully,so the effect won't spread around corners the way it does for slower-moving effects like fireball and stinking cloud.

I guess it's up for interpretation, but I certainly never got the idea that fireball was at all slow-moving.

It also makes for better game-play by encouraging players to seek total cover from the dragon's breath. But, I'd also buy the argument that the developers simply left off that "extends around corners" text for the sake of brevity and simplicity.

The spirit of Jeremy Crawford appears and intones, "If thing X was supposed to do Y, its description would say so."

This may be one of those areas where the DM's judgement needs to take over; for example, if the dragon breaths fire into a small stone room, the fire might curl around and fill the room even if that's outside of the area of the cone (sort of the way fireball used to fill areas by volume, except without forcing the DM to halt the game and perform multi-dimensional calculus).

I'd only do that if I knew that the players were well aware it worked that way.

Finally, maybe the point of my OP got a little bit buried in my babbling. My intent was to pose the following questions:

1. Is there a general rule that I have overlooked that answers for non-spell area effects the question(s) that the spell AE rule that I quoted answers for spells?
2. If not, is it reasonable to conclude that non-spell AEs are supposed to follow the rule (that I quoted) for spell AEs?
3. And even if we can't decide that it is RAI for the non-spell AEs to follow the spell AE rule, is that a plausible/acceptable/good (your choice) way to adjudicate them?

Any thoughts on those?


* Ok, ok. Technically that is the definition of a closed ball and the sphere is its surface, but that is not a nicety that D&D has ever observed.

 

[Harzel]

The text you quoted is part of the Area of Effect section, so I'd apply that as well of course. That is unless the ability description says otherwise.

Banshee's Wail is very specific in how it works and doesn't even refer to an AoE type.

Here are some spell descriptions that also do not explicitly refer to any AE shape. Would you say that these are or are not AE spells? My take is that they are. (Obviously, Ice Knife has a couple of parts. I am referring to the explosion part.)

Destructive Wave - You strike the ground, creating a burst of divine energy that ripples outward from you. Each creature you choose within 30 feet of you must succeed on a Constitution saving throw or take 5d6 thunder damage, as well as 5d6 radiant or necrotic damage (your choice), and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone.

Ice Knife - You create a shard of ice and fling it at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 piercing damage. Hit or miss, the shard then explodes. The target and each creature within 5 feet of it must succeed on a Dexterity saving throw or take 2d6 cold damage.

Antilife Shell - A shimmering barrier extends out from you in a 10-foot radius and moves with you, remaining centered on you and hedging out creatures other than undead and constructs.

Warding Wind - A strong wind (20 miles per hour) blows around you in a 10-foot radius and moves with you, remaining centered on you.

If the wording of Wail were instead, "All creatures within a 30 ft. sphere centered on the banshee ...", it would be logically equivalent, I think. Do you disagree?

Also, I am not sure what you mean when you say Wail is 'very specific' nor what you think the conclusion from that is. Most D&D effect descriptions are pretty specific; is there some way in which Wail is more specific or specific in some special way? Sorry, I'm just missing your point.

 

[Rya.Reisender]

I guess you got a point.

If it says "Everyone within 30 feet of you", it doesn't really refer to an AoE, so there's no definition on what the point of origin of that AoE is, so consequently it's impossible to determine if there's line of sight between point of origin and the target. So by RAW (but probably not RAI), I'd say it works around corners and even through walls.

For creature abilities, that's perfectly okay. I - the DM - will voluntarily opt to not ruin the fun for my players by having all the monsters kill them through walls without them even having a chance to fight back.

For spells which any PC can cast, it kind of ruins the fun if you allowed your players to attack through walls. So it might be better to rule that each spell that doesn't refer to an AoE, still has a point of origin which you can take from the flavour text:

- Destructive Wave - Point of Origin=Caster ("ripples outward from you")

- Ice Knife - Point of Origin=Shard ("the shard then explodes")

- Antilife Shell - Point of Origin=Caster ("extends out from you")

etc.

I guess this handling is reinforced by some spells actually specifying that they work through walls which would indicate they usually don't.