Enough monsters. Back to magic. But just kind of a rambling set of thoughts about the senses.
I have a beef with two second level spells: silence for the bard and cleric (okay yes ranger also); darkness for the sorcerer/warlock/wizard.
Silence is weird. In OD&D, the text isn’t specific (or so I’ve been told) about how it interacts with spellcaster’s spell components. These days, I think it’d be hard to switch it from the wizard-shutdown it is, because so many other mechanics-first aspects have used it in that sense. It’s odd to have that rider effect in the first place; in 5e we loosened the restrictions on somatic gestures and grappling (pun intended; somatic gestures require a “free hand” but even restrained doesn’t explicitly remove that, so I’m pretty sure it’s intended to keep somaticking away). It’s philosophically weird, too: it’s an illusion effect that somehow prevents the universe from hearing your verbal components.
Darkness is weirder. It offends my physical intuition. D&D5e has a fiction that it has 3 light levels (bright, dim, and dark), but I count at least two more: sunlight and magical darkness. Most creatures collapse the first three categories into the first category, because of the ubiquity of darkvision. Devils have this whole rigamarole around devil’s sight being able to pierce magical darkness, but there are only 2 effects which cause magical darkness, as far as I can tell: darkness and the aura of a darkmantle. Okay, yes, hunger of hadar covers its area with magical blackness, but it also blinds targets completely within the area: it’s splitting the difference. Darkness is an evocation effect (like light, the effect it has on the magical equivalent of photons is real). Comparing it with the same-level invisibility and blur and the lower-level fog cloud is instructive. The first two are both personal illusion spells which hide objects (the first completely but the target can lose it easily, the second much less so, but with no ability to break it). The last has the same real effects as fog cloud, but it’s bigger, a level lower, and is described as fog instead of darkness, so its spell interactions are a bit dissimilar. Oh, and fog cloud is immobile, while darkness follows objects.
In both cases, the darkness and silence spells are sneaky-sneak spells that get (very quickly) repurposed to be combatty-combat spells, and which prove so much better at that latter use that I think we forget this history. Compare with the 2nd level abjuration pass without trace (druid, ranger): pure sneaky-sneaky with its +10 to Dexterity (Stealth), and some outdoorsy mostly cosmetic riders. That’s what I want these to be: any combat potential it has derives strictly from its stealth. And by the by, when did abjuration take on the responsibility for shadows and quiet?
Silence should absolutely be broken in half: Firstly, an additional option on blindness/deafness: mute, which robs its victim of speech and the ability to make noise (no signal bells, no banging on doors), which shuts down spellcasting but permits a saving throw every round. Secondly silence, which dampens sound and permits stealth in its current wide area, granting resistance to thunder damage and a large bonus to stealth to creatures in the area when the effect is created, but same restrictions on its target as invisbility (so, super easy to break, and therefore no offensive uses).
Darkness needs a different fix. I have always loved the face-shrouded-in-shadow light-drinking-aura thing. To me, that sounds an awful lot like blur. If we give blur the additional text “if you are in the area of a light spell of 2nd level or lower, it is dispelled”, I think we’ve covered half our problem space. It’s not even the problem space of the darkness spell, just an interesting power most agents of night should have.
If I claim powers-of-night use illusions, devil’s sight would have to grant them some measure of immunity to blur (, mirror image, invisibility, … 🙂 ) Why not grant them limited truesight? Lying to a devil doesn’t seem to me to be a winning move. This also seems like a purely-reasonable change.
If you just want to shroud an area in blackness, use the fog (smoke, night airs, whatever) created by fog cloud. You can of course use a variety of illusion effects to declare an area night-shrouded instead, with interesting results. Silent image creates objects, creatures, and visible phenomena and can be moved: I would definitely permit night-shrouded as an effect. It even has the bonus that if you’re in on the joke, the illusion doesn’t block your sight. It’s a level lower. I’d definitely let you upcast silent image to grow the area.
If that’s what we expect darkness to do, our daylight spell should probably affect illusions of third level and lower within 30 feet, since I’ve repurposed “illusion” to mean “darkness”. It’s a third level spell being used for nothing more than a light radius, so even an invisibility purge-like effect doesn’t seem like overkill to me: illusions of 3rd level and lower are stripped and dispelled if they enter the aura. Done. Truesight, coming up in 2 levels, will really eat illusion’s lunch, so I don’t even mind.
That’s fine and dandy as such things go, assuming you’ve bought into my essential complaint that darkness is weird and broken.
But what if you do want negalight, a torch whose light is inverted? I really like the idea, but I fear that D&D’s light physics leave it out of our grasp, except for the way that 5e has already implemented it. You could treat areas within the torch’s 40 foot radius as a sort of visual difficult terrain — “each foot of distance in the aura counts as two feet of distance for vision”. I actually like that very much: it clearly affects torches and darkvision, and could be stretched to include missile weapons and spell ranges too if the DM wanted. But that’s so much work to go through for the relatively minor payoff: You spend a minute with a ruler figuring out precise distances, and then just give an attack disadvantage.
So much easier to declare that negalight blocks and is blocked by light. As the existing darkness spell does. That’s life, I guess.