Dragon Tactics, Part 5: Deep Dragons and Sea Serpents


Deep dragons present a subterranean variation on the chromatic dragon theme. They exist in wyrmling, young, adult and ancient variants, just like their chromatic cousins, and share a sequence of features and traits that they acquire according to the same pattern as they age. Their challenge ratings are lower, however, since they have fewer hit points, deal less damage than even white dragons, and lack the Frightful Presence trait; we might think of them as degraded versions of the chromatics.

Like their kin, deep dragons are melee-favoring brutes, with Strength as their primary offensive ability and Constitution as their primary defensive ability. Despite living underground, they can fly as fast as their skyborne relatives, and they can also burrow and swim. Sadly, lacking the Tunneler trait, deep dragons have no way of burrowing through solid rock; they have to make do with whatever passages nature carves for them. But they’ll certainly favor caves with large halls, and flooded areas are a plus—to an extent. Unlike green dragons, deep dragons aren’t amphibious and have to hold their breath underwater. That’s no big deal, though: Fifth edition Dungeons & Dragons’ suffocation rule is generous, as long as you can take a deep breath and hold it before you dive. Deep dragons also have exceptional darkvision—90 feet as wyrmlings, 150 feet later on—so they have no reason to light their lairs, and they love locations with straight passages and long sight lines, which allow them to see other creatures long before they can be seen themselves.

They have proficiency in the ambush skills of Perception and Stealth, but they also have proficiency in Persuasion. To confabulate with a deep dragon wyrmling, you’ll have to speak Draconic, but young, adult and ancient deep dragons all speak Common (and Undercommon) and also have high enough Wisdom and Charisma that they’ll stop fighting and parley if a combat encounter is going awry for them, generally when they’re moderately wounded (for a young deep dragon, reduced to 65 hp or fewer; for an adult, reduced to 102 hp or fewer; and for an ancient, reduced to 140 or fewer).

This point merits a digression. How do you use a social skill like Persuasion against player characters when players have free will and full dominion over their PCs’ thoughts, feelings and choices? You do it by using your authoritative Dungeon Master voice to present the point of view of a creature or nonplayer character as if it were fact. It’s fairly easy to do with Deception or Intimidation—you tell the player that whatever the character or creature wants the PC to believe is true, DM’s honor—but it’s trickier when the opposing character or creature uses Persuasion. With that skill, a lost contest means the PC’s judgment is overwhelmed by the argument, which you need to convey by making it your argument. In other words, reiterate the logos, ethos and pathos of the appeal out of character, speaking as yourself. If the PC’s Insight prevails, on the other hand, present the actual facts of the situation instead. In the case of a strong argument, that might mean reiterating how strong it is, but in the case of a weak one, it reveals the weaknesses.

Beyond these basics, deep dragons fight the same way their chromatic kindred do: They stay in the air if they can, land when they must, use their breath weapon whenever it’s available and they can hit enough targets with it, and otherwise Bite (wyrmlings) or Multiattack (all others). Deep dragons’ breath weapon is Nightmare Breath, which deals psychic damage and can impose the frightened condition; imagine that they’re exhaling hallucinogenic spores that send their targets on a bad trip.

Adult and ancient deep dragons have legendary and lair actions, as chromatic dragons do. Tail is an opportunistic whack at an enemy who tries to get cute and outflank them, or who thinks they’re far enough away to avoid being hit but aren’t. Commanding Spores is useful for making one of a pair of adjacent enemies attack another, but it’s even better if the attacking enemy is engaged in melee with a deep dragon who’d rather be somewhere else at the moment, because when it works, it wastes the enemy’s reaction, allowing the dragon to withdraw without risking an opportunity attack. Spore Salvo is best against shock attackers such as rogues and monks: They have to be close enough for the spores to reach them, but they also have to depend on Dexterity rather than Constitution for defense, so that they’re more likely to fail the saving throw. Being poisoned also makes it harder for a rogue to pull off a Sneak Attack.

Deep dragons’ lair actions follow the chromatic pattern of debilitator (Deep Torpor), movement restrictor (Mossy Sludge) and direct damage (Toxic Spores), although Deep Torpor also restricts movement, and Toxic Spores also debilitates. Deep Torpor is another feature that’s great to use against rogues and monks, because it hoses their action economy, and Toxic Sludge is deep dragons’ only source of area-effect damage beyond their breath weapon, for use against four or more clustered targets.

Deep dragon wyrmlings retreat when reduced to 10 hp or fewer; young deep dragons, 37 hp or fewer; adult deep dragons, 58 hp or fewer; and ancient deep dragons, 80 hp or fewer. Wyrmlings and young deep dragons engaged in melee Disengage before withdrawing if running, swimming or flying away, but they Dash without Disengaging if they’re burrowing. Adult and ancient deep dragons engaged in melee always Disengage first.

Sea serpents are marine ambush predators. They’re Amphibious, but they’re slow on land and strongly prefer to stay in the water; the only time they’ll come out is to attack an opponent on the deck of a ship or to pursue one a short distance on land, and they break off pursuit once their quarry flees beyond the reach of their breath weapon.

Young and ancient sea serpents alike are brutes with formidable Strength and Constitution and proficiency in Perception and Stealth. They have 120 feet of darkvision, useful at depths where sunlight doesn’t penetrate, but also predisposing them to make surface attacks only at night. And they share the Siege Monster trait, which means that before they attack their victims, they attack their victims’ vessel, crushing it to matchsticks with their Constrict attack and chomping through the hull with Bite. If the vessel is Large or smaller—a rowboat, for instance—Constrict can grapple and restrain it. Once their victims’ vessel is destroyed, sea serpents pick the tasty morsels out of the water one by one.

They save their Rime Breath for when their targets are adrift and helpless, since it deals damage only against creatures, not against objects or structures, and they first position themselves where they can strike at least three targets in the area of effect. They always favor their Rime Breath over their Multiattack when it’s available. When they do use Multiattack, they Constrict before they Bite, to try to gain advantage on the latter by restraining their targets. As a Multiattack option, Tail is inferior to Constrict in most cases, since its reach is equal or less, it always deals less damage, and restraining an opponent is stronger than knocking them prone. The only reason to prefer Tail over Constrict is if a troublesome melee opponent needs to be shoved away.

When all their foes are fleeing, they pursue, but when one or more are unconscious, sea serpents pause in their pursuit to gobble them up with coup de grâce Bite attacks. Ancient sea serpents can do that more effectively than young ones, since they can Bite as a legendary action. As a legendary action, Tail is most entertaining when employed as retaliation for a successful hit.

Sea serpents retreat when seriously wounded (for a young sea serpent, reduced to 49 hp or fewer; for an ancient sea serpent, reduced to 68 hp or fewer).

Next: dragon turtles revisited.

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15 responses to “Dragon Tactics, Part 5: Deep Dragons and Sea Serpents”

  1. WaserWifle Avatar

    Ah, Deep Dragons, just in time! I’m going to be using one soon, been wanting to for a while. I’m happy to see that some of their features are highly effective against rogues and monks, I have both in the party I run. Their regional effects are pretty funky too, if a bit at odds with each other: Restless Sleep wears down anyone camping in the dragon’s territory, great for wearing people down as they try and navigate their way through the overgrown winding tunnels, but Verdant Growth makes it easier on guests. I suppose with its poison immunity, food for the dragon needn’t be the same as food for adventurers, but I don’t feel like that’s intended. Easy enough though to invoke the “one or more” clause, and only apply the one that suits your game.

    The only thing really that trips me up on this stat block is Change Shape. A cool ability, but how does the dragon use it? Without deception proficiency, its not got any special talent for disguising itself beyond its good charisma. And while it can change into any creature, its game statistics remain the same, thus not benefiting from any special abilities. This features would make sense as a disguise against someone who has never met the dragon and doesn’t know it can shapeshift, or just to shrink to fit through small openings, but otherwise has limited usefulness. If it wanted to pass as a humanoid for example to outsiders, might might need some complicit underlings (drow, duergar, deep gnomes, myconids or some other intelligent underdark dweller) and only reveal its true draconic form when it comes time to have a boss battle.

    1. JP Avatar

      Your description of Change Shape’s effects do not line up with the Change Shape effects for metallic dragons; unless deep dragons received updated text for their Change Shape, they would absolutely get the special abilities of the humanoids they shifted into, just not Class Features.

      1. WaserWifle Avatar

        Perhaps there’s been different prints of the book, but according to mine, Deep Dragons, Gem Dragons, and Metallic Greatwyrms all retain all their game statistics bar size when they change shape. Although to be fair, there aren’t that many good reasons for a Greatwyrn to assume the statistics of something else.

        1. JP Avatar

          I don’t own Fizban’s yet (though I aim to soon), so I can’t evaluate the text in the book. I can only evaluate the text for Change Shape for Metallic Dragons, which I am assuming is similar. If you compare those texts, you will be able to see if they differ in any way. If they are identical, then they work the same way.

          The text for Metallic Dragons specifically says that they only keep their HP, proficiencies, Legendary Resistances, and mental statistics when Changed, and otherwise assume the stats of their new form, excluding class features. This means, for instance, that an Adult Gold Dragon could Change Shape into a Warlock of the Archfey (from Volo’s) and get access to that archetype’s Conjure Fey, since it is classified as an innate spellcasting feature. It would not get access to the cantrips, however, since those are classified as a warlock/pact magic feature.

          The way you speak about the Change Shape feature for Deep Dragons leads me to believe that the text is significantly different, but it’s worth evaluating all the same. If it is different, that’s a significant nerf to a powerful ability.

          1. Keith Ammann Avatar

            It is different. Metallic greatwyrms and deep dragons retain all their stats in their humanoid form, except for size. As for why … isn’t disguise enough? And how much do you really need Deception proficiency when no one has any reason to question whether you’re anything but what you appear to be?

          2. WaserWifle Avatar

            I did compare the texts, that’s what I’m saying. They’re different features, I checked. The new dragons can turn into any creature, but no stat change. Takes one action for Deep Dragons, or a bonus action for Gem dragons. As for whether its a nerf or not, I think that’s the wrong question. I believe it was probably done for simplicity sake, so you don’t have two different stat blocks up on your DM screen or too many bookmarks in your monster manual and cross reference them just to run one creature. However, dragons are generally strong enough that they seldom gain much from turning into a humanoid or beast, so if I was considering the strength of the feature relative to that of MM dragons, I wouldn’t say its much of a downgrade. I have a very neutral opinion on this.

    2. shikomekidomi Avatar

      Lots of things one can do with Change Shape. For example, have small holes connecting rooms in their lair that the dragon can turn into a snake and slither through. Keeping the dragon’s statistics in the process even means they aren’t putting themselves in danger of assassination or predation by doing so. Being able to turn into, say, a Drow, might not fool any particularly observant members of the species, but it would certainly make visiting their cities and fitting in their libraries easier (given their lair effects, I’m assuming Deep Dragons like books). Manipulating objects (magical or otherwise) that require hands instead of talons is, likewise, sometimes very useful.

      1. WaserWifle Avatar

        These are pretty much the uses I had in mind for the feature when I decided to run a Deep Dragon. Maybe its no disguise expert, but barring magic, a casual observer can’t see through the disguise, unless they had prior knowledge of a shape-shifting dragon. Good for blending into crowds where you’re not under direct scrutiny. And bearing in mind, unlike the Monster Manual metallic dragons, the deep dragon isn’t limited to humanoids or beasts. If it wants to leave false tracks of an umber hulk, smaller dragon, myconid etc than it can. It can lead a band of troglodyte minions on a raid and leave any witnesses swearing up and down that it was just an ordinary troglodyte raid. People familiar with dragons would know that bigger = stronger, so you can cause adventurers to underestimate you.

        And of course, since the one I plan on using is the Ancient variety, getting through small spaces is fantastically useful. They can’t easily tunnel through rock, so underground being that gargantuan could be a hindrance otherwise.

  2. Manateeman1313 Avatar

    The Deep Dragon Change Shape ability is different than the Metallic Dragon Change Shape ability. The Deep Dragon’s stats aren’t replaced, except for size.

  3. shikomekidomi Avatar

    Since this is the Deep Dragon discussion page, I suppose I should mention why I consider Deep Dragons more like evil Gem Dragons rather than colorless Chromatic dragons. Or perhaps they are some kind of missing link or hybrid race between the two. It’s probably not directly relevant to their strategies, but it is potentially interesting.
    First: They have two elemental resistances and no elemental immunity. This is the same as all types of Gem dragon but different from Metallic or Chromatic Dragons.
    Second: They have a breath weapon that deals damage with a rider effect. Again, the same as Gem Dragons, but different from the just damage of the Chromatic or the Metallic’s two breath weapons, one for damage and one for negative effects.
    Third, the Lair effect of an increase in a particular type of edible life around their den (fungi in their case) is a common, though not universal, feature among Gem Dragons and largely unknown among Chromatic.

    1. shikomekidomi Avatar

      Almost forgot, the fourth reason: They have Change Shape, again like Gem and not like Chromatic dragons.

      Admittedly, part of the reason for some of these may be that some of these things are new ideas they came up for with Fizban’s that they hadn’t thought of yet when writing the Monstrous Manual, but others like the elemental resistances seem more deliberate changes away from the Chromatic line.

      1. Keith Ammann Avatar

        Personally, I think the new wording of Change Shape is less tied to lore and more written that way to save DMs the trouble of looking at two different stat blocks and figuring out which numbers from each apply.

        1. shikomekidomi Avatar

          Certainly. But that doesn’t take away from the fact Deep Dragons have Change Shape and no Chromatic Dragons do, it’s just an argument that we probably shouldn’t consider their (and Gem Dragons) Change Shape as meant to be different from Metallic Dragons.

  4. Fireslayer Avatar

    Thank you, Keith, for the tips on Persuasion! I’ll keep that in mind whenever my players wish to parley (which I plan on them doing).

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