As you may know, we’re working on “Under the Seas of Vodari,” a Kickstarter stretch goal supplement for Seas of Vodari. D&D has rules for magical interactions underwater, but if all or much of the campaign takes place there, maybe you want to cut out things that underwater spellcasters never would bothered to hand down from generation to generation. (Reposted from Harbinger of Doom.)
- I’m only covering the SRD here, because this is for an OGL-based product.
- I’m trying not to make too many assumptions about the ancestries that might be casting these spells, but we’re still working in existing mechanical parameters. For example, darkvision usually comes in 60-ft range. 120-ft darkvision is rare and probably carries a drawback, and any other range is a unique case.
- Fire spells in general going to be incredibly tough sells for underwater creatures, though fireball in specific is overpowered enough to almost still be a good idea when its damage is halved. That said: technically, being immersed in water grants resistance, so Elemental Adept (Fire) solves that problem.
- Spells that involve melee or ranged weapon attacks are rare, though not unheard-of.
- Almost all underwater action cares about the z-axis.
- Unless a spell specifically talks about interacting with water, I’m assuming that water is not an object that causes collision, because if it were, the Player’s Handbook would have mentioned that. (F’rex, casting disintegrate doesn’t disintegrate a big cube of water next to the caster’s hand, any more than it disintegrates the air next to an above-water caster’s hand.)
Let’s get the first thing out of the way: almost no material components of the Player’s Handbook spells work. Acid arrow – the first spell of the SRD, alphabetically – wants a powdered rhubarb leaf and an adder’s stomach. Good luck finding either of those underwater. Other than noting it here, I’m going to assume all spells can just have their components changed to things found underwater.
Alter self needs to include the inverse of Aquatic Adaptation. Aquatic Adaptation is great for getting around the limitations on melee weapons you can use, though.
Bigby’s hand loses a lot of range advantage, but it’s otherwise fine. Pleased to see that Interposing Hand functions in the z-axis.
(Evard’s) black tentacles doesn’t play nicely with the z-axis, so a lot of creatures would just swim over the space you define. Fix this by defining the area as a cube rather than a square, maybe.
Blade barrier offers a height of up to 20 ft, but that’s still only okay in a 3D environment. (You might be fighting a completely vertical battle, for example.)
Branding smite requires a melee weapon attack. We can assume that PCs have a way to deal weapon attacks that don’t suffer disadvantage, though.
Burning hands is, of course, a fire spell.
Conjure elemental has one of its options locked out (because being underwater instantly kills a fire elemental).
Conjure fey – well, you can conjure fey aquatic beasts, but your options are very constrained overall.
Conjure minor elementals – see above.
Control weather – does water interfere with a “clear path to the sky”? Probably. But if you’re substantially below the surface, none of the surface weather even matters.
Delayed blast fireball – fire spell, blast radius larger than some expected encounter distances
Entangle – you’re often not going to be in contact with the ground or in the space adjacent to the ground (this affects only a square area, not a cubic one. Any clever DM would have this affect kelp and any other underwater plant life, even if you’re not adjacent to ground.
Fear – limited visibility might mean that the creature isn’t far away at all before it can’t see you, and can start making saves.
Fire bolt is a fire spell.
Fire shield is sometimes a fire spell, and when it’s not a fire spell, you already have resistance to fire damage, so the spell can’t grant that (but it can deal retributive cold damage). Not useless, but constrained.
Fire storm is a fire spell.
Fireball is a fire spell.
Flame blade is a fire spell.
Flame strike is partially a fire spell.
Flaming sphere is a fire spell.
Grease affects a surface the target stands on, in the way swimmers don’t, and just generally doesn’t make a ton of sense underwater.
Heat metal is a fire spell.
Hellish rebuke is a fire spell.
Meteor swarm is a fire spell, and has the longest range of any conventional attack spell in the game.
Planar ally has very few options with a swimming speed or the ability to breathe water.
Planar binding, same
Produce flame is a fire spell.
Scorching ray is a fire spell.
Spike growth is about contact with the ground, which most enemies can avoid.
Sleet storm does almost nothing, since you don’t have to stand on the ground. There are much easier ways to generate heavy obscurement. (Also there’s the fact that aquatic races would never have the idea to create this spell.)
Wall of fire is a fire spell.
Dead on Arrival
Animate dead doesn’t explicitly include the movement modes of the original humanoid, so your skeleton or zombie doesn’t have a swimming speed and has disadvantage on attacks with weapons other than daggers, javelins, shortswords, spears, or tridents.
Animate objects technically falls under the same rule: the “creatures” don’t have a swimming speed, so they make all of their attacks with disadvantage.
Call lightning requires line of sight to a point 100 feet in the air.
Conjure celestial – pretty sure there aren’t any water-breathing celestials?
Conjure woodland beings – none of those fey are water-breathing by default.
Create undead – see note on animate dead, but at least aquatic ghouls/lacedons have more legacy in D&D.
Earthquake isn’t quite useless, but a whole lot of underwater encounters are going to take place with none of the characters in contact with a solid surface. If you add shockwave/tsunami effects on the water, this spell could go back to its intended power level, maybe. It’s also about its long range – 500-ft range, 100-ft radius – and neither of those suit underwater engagement distances.
(Mordenkainen’s) Faithful Hound doesn’t have a swimming speed, so disadvantage on attacks.
(Tenser’s) Floating Disk gets weird underwater, because it interacts so strangely with the z-axis. Rabbit points out that it could be used to stop something from rising, and that’s pretty interesting.
(Otiluke’s) Freezing sphere specifically calls out that it has idiosyncratic effects if it strikes a body of water… and there’s always a body of water. In fairness, you might find a situation where that handling is what you want, but it’s going to be rare.
Gaseous form explicitly doesn’t work, because it has handling for liquids.
Giant insect doesn’t include any aquatic insects; “the GM might allow you to choose different insects.” We need stats for giant aquatic insects and arachnids.
Levitate – the spell is pretty useless for helping allies move, and possibly useless for holding swimming enemies in place (as one can do to non-flying enemies above the surface).
Locate creature has a clause about failing if there’s 10 ft of running water between you and the target.
Phantasmal steed creates a riding horse with a land speed. It’s not hard to imagine a water variant with a swimming speed, of course.
Reincarnate needs a variant list feature aquatic races.
Shillelagh uses clubs or quarterstaffs, which aquatic races probably wouldn’t use in the first place.
Tree stride is probably not a thing, except for the rare cases that a formerly above-water area is flooded.
Arcane lock might be fine… do underwater peoples build doors, windows, and storage containers, or is that way of organizing space irrelevant to them for some reason? Rabbit makes an interesting argument that corrosion from saltwater means metal locks might not be A Thing, so this might be an incredibly important form of security.
Blindness/deafness – I’m not looking it up right now, but it seems like a lot of aquatic creatures would be less reliant on sight, since light is so much scarcer.
Blur specifically doesn’t work if the attacker isn’t relying on sight, so see above note.
Cloudkill requires a judgment call, but it talks a lot about air and fog. Formally, you just kinda “go with it” in 5e, but I think it’s asking for player/DM arguments.
Comprehend languages raises questions about written communication in an underwater society. Knotwork? Stone or metal engraving?
Create or destroy water – it’s not at all clear whether this would do anything. The “in an open container” clause is confusing, and… I mean, the ocean can refill anything you can destroy instantly, yeah?
Demiplane says it creates an empty room – doesn’t say anything about letting water through, but I think we can assume that a demiplane created by an aquatic creature while underwater is full of water. Otherwise the spell is probably just about useless to them.
Find steed is a reminder that we need to write a decent variety of underwater steeds.
Fly – I think flying speeds work underwater as if you’re in air, if they’re magical and not wing-based? I can’t find a rule on it right now.
Fog cloud might be allowed by the most technical reading of rules, but… I mean, you can’t have fog underwater. See also cloudkill.
Guards and wards mentions fog and stinking cloud effects. Same issues as cloudkill. Also, gust of wind.
Gust of wind – presumably a DM would be wiling to treat this as a blast of water current.
Illusory script – what are we doing with writing and written media?
Incendiary cloud – cloud spell. Also, fire spell.
Jump – do you have a jump distance underwater? Unclear, if you’re not walking on the bottom of the body of water.
(Otiluke’s) Resilient sphere – there’s no explicit handling for z-axis movement, so we might want to make a note for that? Or not, whatever.
Reverse gravity presumably doesn’t work unless the target(s) are not buoyant.
Stinking cloud is a cloud spell.
Storm of vengeance offers some room for interpretation, but a whole lot of the effects are at least harder to imagine underwater.
Wind walk is a cloud-related spell.
Acid arrow’s 90-ft range is great on the surface, but the DMG suggests that 60 ft is the starting encounter distance under optimal visibility conditions. In fairness, this is quite a long way in a dungeon encounter.
Alarm – notably it wards a cube, not a square, even though you’re using the wire to mark a mostly-2D space.
Antimagic field works fine, as long as you don’t need magic to breathe or swim. If you’re fighting someone who does need magic to breathe or swim, you can mess ‘em up real good.
Augury is fine, but I’m interested in what underwater peoples use for fortune-telling.
Awaken is fine, though some guidance on what stat block to use with awakened coral wouldn’t be bad.
Banishment is just a reminder that we need aquatic fiends.
Barkskin is mechanically fine, thematically a bit weird. Because… bark. Easily renamed.
Beacon of hope
Blight could have an unusual interaction with coral, as a large group of creatures?
Blink – a technical read of the spell might grant improved visual range in some cases, if your vision isn’t impeded by murky water while in the Ethereal.
Chain lightning works fine, though you’re never getting that 150-ft range.
Chill touch – huge range that you’ll never use, but that’s okay.
Circle of death – you don’t need to see targets, so go nuts with that 150-ft range.
Color spray – relies on blinding targets, but it’s 1st level, so… kinda who cares.
Commune with nature is fine, though questions about bodies of water are unlikely to be helpful.
Compulsion specifies that it only compels movement in the x- and y-axes. That could be relaxed underwater, but it still works fine even if you don’t do that.
Cone of cold is fine; I’m amused by the idea of someone floating upward once frozen, because ice floats.
Conjure animals works, you just want to conjure aquatic animals. We should make sure there are aquatic beasts at all listed CRs.
Contact other plane
Contingency – with the very minor note that its condition requiring you to keep the material component in your possession may be more complicated with the stowing solutions available to aquatic people.
Continual flame – even better underwater.
Control water – this is very good underwater, even if the Flood option doesn’t really make sense.
Create food and water
Detect evil and good
Detect poison and disease
Dimension door – this works very well underwater, in that teleporting upward is usually going to be a survivable environment, rather than falling to your death. Teleporting in the x- and y-axes is probably equally (?) likely to run into a solid object as above the surface.
Disguise self works fine, and we’ve discussed a bit of how universal access to it affects voda society.
Dispel evil and good
Dispel magic works fine, and it’s deadly against surface-dwellers who are using water breathing to survive. Same for any water-breathers using magic to let them go above, I guess.
Druidcraft works in general, but a lot of the specific examples need reimagining to suit nature underwater.
Eldritch blast – long range notwithstanding.
Enlarge/reduce – since this doesn’t mention changing your buoyancy. 😉
Eyebite, with standard disclaimer about limited visibility underwater
Fabricate works, though it also calls out for an equipment list customized to underwater cultures.
Find familiar – notable for having extant handling for underwater adventures! Though none of the aquatic options are anywhere near as good as owls.
Find the path
Find traps, though I’m real curious about what traps look like in aquatic adventures!
Finger of death – though zombies don’t have a swimming speed. (You were never casting this spell for the sake of the zombie.)
Flesh to stone definitely decreases the target’s buoyancy! The joy of sending someone straight to the midnight zone can’t be overstated. Finding a garden or pile of statues in the deeps would be awesome.
Freedom of movement – a survival spell for surface-dwellers who go underwater, incidentally.
Gate, with a minor note around no water-breathing fiends.
Globe of invulnerability
Glyph of warding – just don’t use the fire version. You have other options.
Guardian of faith
Hallucinatory terrain – it doesn’t SAY you can (or can’t) change the appearance of the terrain to “exactly as it is, but well-lit,” but that wouldn’t actually be OP for a 4th-level spell.
Heroes’ feast – though I’ll be particularly amused to hear how people replace the expensive material component on this one, since it’s so specific and so often discussed.
(Tasha’s) Hideous laughter
Hypnotic pattern – I think we can safely ignore the explicit reference to “air” in the text.
Ice storm – narratively weird, mechanically fine
(Drawmij’s) Instant summons
(Otto’s) Irresistible dance
Lightning bolt – though… huge AoE, way outside your likely perception range.
Locate Animals or Plants
(Mordenkainen’s) Magnificent mansion
Mass cure wounds
Mass healing word
Meld into stone
Mirage arcane – this works, though the effect might be really bizarre (creating an illusion of the surface world).
Mirror image is still mostly fine, though it’s going to get tripped up on unusual sensory modes by underwater creatures a tiny bit more often than above water.
Pass without trace – though I have questions about how much tracking is an element of underwater life
Plane shift works fine… as long as you remember that we’ve written planar locations up to this point to appeal to air-breathers, not water-breathers.
Poison spray – even with all of my commentary on clouds and gases, this one is particularly easy to imagine underwater.
Power word kill
Power word stun
Prayer of healing
Prismatic spray includes fire as one of its seven effects, but it won’t even come up in a lot of castings.
Prismatic wall includes fire as one of its effects, and might be harder to dismantle depending on the DM’s ruling around gust of wind.
(Mordenkainen’s) Private sanctum
Protection from energy – the fact that you always have fire resistance doesn’t make the spell useless, after all
Protection from evil and good – though we’ll need to support a few more aquatic types of everything except aberrations and elementals
Protection from poison
Purify food and drink
Ray of enfeeblement
Ray of frost
Rope trick – casually ignoring the “into the air” bit as not being critical to design intent.
(Leomund’s) Secret chest
Shapechange – you’re working with a different, but not really lesser, list of creature options
Shield of faith
Simulacrum is fine, as long as you ignore the implied buoyancy of “made of ice.”
Spare the dying
Speak with animals
Speak with dead
Speak with plants
Spider climb – this one is actually really cool. You don’t need it to allow movement, because you can swim anywhere. You use this to resist movement, such as currents going someplace you don’t want to go.
(Rary’s) Telepathic bond
(Leomund’s) Tiny hut – though of course “the atmosphere inside the hut is comfortable and dry” is not quite right here.
Transport via plants – though I don’t really know enough about oceanic plants to know if this can work. (Coral is not a plant.)
True strike – it’s no worse underwater than anywhere else
Wall of force
Wall of ice
Wall of stone
Wall of thorns – not that I’m sure aquatic people would have the idea for this spell?
Water breathing – obvious problem is obvious, but the spell still works. Needs an air-breathing spell to go with it, of course.
Water walk has explicit handling for underwater usage. It’s not helpful for fully aquatic creatures, and it doesn’t allow a saving throw, so that might be a problem in itself.
Wind wall – and personally I’d let this propel a creature upward if they tried to cross it.
Word of recall
Zone of truth
In conclusion – if this content is interesting or useful to you, let me know and I can cover the non-SRD spells, including Xanathar’s Guide to Everything spells.