Astral Dreadnought Tactics

Now that the holiday madness is over, it’s time to get back down to business, and the business of the day is the astral dreadnought, whose name tells you most of what you need to know: This fearless titan drifts through the astral plane, obliterating everyone and everything it comes across.

While its Strength and Constitution are epic, its Dexterity is dismal—a gargantuan beast like this doesn’t turn on a dime. Nor does it possess Intelligence beyond animal level. Its Wisdom is high, however, and its Charisma is exceptional—perhaps reflective of its ability to command awe. Despite its extremes, this is a straightforward brute ability contour, indicating a creature whose approach is to close in and maul.

Its resistances and immunities aren’t all that relevant, because (contra the flavor text in Mordenkainen’s Tome of Foes) its Intelligence is so low, it’s not going to bother to distinguish between one target and another. However, its relatively high Wisdom indicates a prudent, instinctual self-preservation impulse. The astral dreadnought is a creature so unaccustomed to resistance that any prey that can inflict a moderate wound against it (reduce it to 207 hp or fewer—yeah, that number’s not a typo) will give it pause.

That’s not fear, mind you; that’s just surprise. By itself, it’s not enough to make the astral dreadnought retreat. Rather, it triggers an intuitive assessment of the situation, represented by the encounter difficulty measure in the Dungeon Master’s Guide (chapter 3). If the astral dreadnought constitutes a Deadly encounter for its opponents, it pushes obstinately on. If it’s a Hard encounter, it backs off once seriously wounded (reduced to 118 hp or fewer); more on that later. If it’s a Medium or Easy encounter, it backs off immediately. (Yes, it’s possible for an astral dreadnought to constitute an Easy encounter. It takes a party of at least six characters of level 15 or higher.)

Running an astral dreadnought is a somewhat mechanistic affair, because its Intelligence is so low and because so many of its traits are passive (Astral Entity, Demiplanar Dungeon, Magic Weapons, Sever Silver Cord—I call this one passive because cutting the silver cord is such a jerk move, there’s no reason not to do it). The only decisions you need to make as a dungeon master are which way to aim its Antimagic Cone, whom to target with its melee attacks, and when to use its Legendary Resistance and each of its legendary actions.

The Antimagic Cone is interesting—and a bit of a Catch-22 for the astral dreadnought. Its area of effect, a 150-foot cone, is humongous. But like all conical AoE effects, it’s limited to a 53-degree arc. At great distances, this is all-encompassing, but once you get in close, it’s easy to run rings around. That’s the thing about a conical AoE: At a range of 100 feet, it covers a 100-foot swath, but at 10 feet away, it extends only 10 feet side to side. Thus, while the astral dreadnought can use its Antimagic Cone to shut down spellcasters from a great distance, it can’t do anything else to them until they get closer—at which point they can fan out, making it harder for the astral dreadnought to shut them all down.

But Antimagic Cone isn’t just for shutting down spellcasters. The effect suppresses the properties and powers of magic items, too, including magic weapons. And since it has resistance to physical damage from nonmagical attacks, it has a good reason to include magic weapons among the types of magic it wants to shut down. Which means it also has some tough choices to make once its foes rush in and encircle it—and not a lot of cognitive candlepower to expend on making those choices. Whatever it decides, it decides by instinct.

Really, there are only two criteria simple enough to apply: either it aims its Antimagic Cone at the greatest possible number of enemy creatures, period, or it aims it at the greatest possible number of enemy creatures who are doing magic things. Does it possess any kind of sense that suggests that it can detect magical energy? Not that I see. So I think it simply has to do a raw count, making this one of the astral dreadnought’s few weaknesses. However, I think it’s fair to let the astral dreadnought count from farthest to nearest, because in the event of a tie, it seems silly for it not to aim the Antimagic Cone at foes who might plink it with magic arrows or ranged spell attacks. The ultimate power of Antimagic Cone, in the case of the astral dreadnought, is that it forces hostile creatures to come closer if they want to try to hurt it.

That being said, nowhere is it written that the astral dreadnought has to stand still. It aims its Antimagic Cone at the start of its turn, before it gets a chance to move, but since astral propulsion is a matter of will rather than physics, it can move any direction it likes, not just forward. And being Gargantuan, and having a speed of 80 feet, it can barge backward up to 40 feet through any number of foes in order to bring its Antimagic Cone to bear on them. It can also move vertically and reorient itself so that it’s aiming its Antimagic Cone downward or upward, turning that cone into a circle or an ellipse as it crosses its enemies’ plane.

That being said, however, it’s a brute melee attacker first and foremost. Maximizing the effect of its Antimagic Cone is not its end goal. Its end goal is eating people, and for that, it needs its opponents close.

ETA: I occasionally get into arguments with commenters over the topic of facing, which in 5E is optional (not, as some seem to think, nonexistent). Given that the astral dreadnought’s eye and mouth are on the same side of its head, I have a strong sense that it should be able to Bite only in the same direction that its eye (i.e., its Antimagic Cone) is pointing. That doesn’t constrain whom it’s able to attack—it’s very mobile—so much as it constrains its positioning before it attacks. And, as a side note, with its high Armor Class and resistance to physical damage from nonmagical weapons, I don’t believe it pays any particular mind to the possibility of opportunity attacks.

The next question is whom to target with melee attacks, and that’s easy: whoever’s hurting it the most, and if nobody’s hurting it, then whoever seems weakest, because that’s what predators do. If these seem contradictory (why wouldn’t it attack whoever seems strongest?), look at it this way: It wants to eat people. Weaker people are easier to eat, and it can eat them faster, with less hassle. But if its eating is being interrupted by Angus MacBash and his +2 claymore, well, that’s a matter that has to be taken care of so that it can get back to the eating.

One distinction the astral dreadnought does make among its opponents is whether it’s attacking them to eat or attacking them to remove a hindrance to eating. If it’s simply removing a hindrance, it doesn’t need to get closer than 20 feet to them in order to attack with its claws. If it’s eating, then it wants to be no more than 10 feet away, so that it can finish its Multiattack with Bite. (I was uncertain whether it was possible for the astral dreadnought to use Claw twice, as part of its Multiattack, if it weren’t near enough to any target to use Bite. Jeremy Crawford was kind enough to answer my question: “A monster can use its Multiattack even if one or more of its attacks have no chance of hitting.”)

However, this is the opposite of what its opponents are trying to do: the targets of Bite attacks will generally want to get as far away as possible, while those who are managing to hurt the astral dreadnought will want to keep doing it, which means staying within their own weapons’ reach. Take the above, then, as a guide to how the astral dreadnought uses its opportunity attacks. If a prey-snack tries to move away, it Bites as soon as they start to move more than 10 feet away. If a serious combatant starts to move away, however, it waits until they get more than 20 feet away, then uses Claw to make its opportunity attack—or maybe doesn’t even bother.

The astral dreadnought’s Multiattack order is always Claw/Claw/Bite unless the first Claw attack reduces a target to 34 hp or fewer, in which case it Bites that target immediately afterward, or an incapacitated opponent is within reach of its Bite, in which case it Bites that target first, then uses its Claws. If appropriate targets aren’t within reach, it first moves to pursue its most effective attacker—or, if there is none, its most desirable prey.

An astral dreadnought’s saving throw modifiers are fairly strong, but it does have its weak points: Intelligence most of all, but also Charisma and Dexterity. Intelligence saving throws are typically efforts to see through illusions; these aren’t do-or-die rolls. Dexterity saves are for dodging damaging effects, but the astral dreadnought has a lot of hit points. Charisma saves—well, there are two things that account for about 80 percent of these, bane and banishment, and Astral Entity prevents it from being banished. Plus, it’s not strategic—it’s a creature of instinct. So I’m inclined to conclude that it uses its Legendary Resistance reflexively, every time it fails any type of saving throw, until it has no uses left.

The astral dreadnought has three legendary actions: Claw, Donjon Visit and Psychic Projection. Donjon Visit costs 2 legendary actions, and Psychic Projection costs 3. It stands to reason that the bar to clear for Donjon Visit should be high, and for Psychic Projection, very high.

Let’s look at Psychic Projection first. “Each creature within 60 feet”—so this is essentially a spherical area of effect with a 70-foot radius (since it emanates from the perimeter of the astral dreadnought’s occupied space, not from its center). Per the good ol’ Targets in Area of Effect table (Dungeon Master’s Guide, chapter 8), this would indicate 14 targets. Well, that’s too high a bar to clear. Let it suffice to say that it uses Psychic Projection as soon as it has all three of its legendary actions available and all its opponents are within 60 feet of it.

Even that criterion seems awfully steep, doesn’t it? Well, yeah. Psychic Projection consumes all three legendary actions. Extreme cost demands extreme justification. But all right, I’m a softie: Let’s say that it also uses this legendary action, if it can, as a reaction to being moderately wounded (as mentioned above, reduced to 207 hp or fewer) when at least two-thirds of its opponents are within range, and again as a reaction to being seriously wounded.

Donjon Visit is ideally suited for removing a bothersome belligerent from play—let’s say, any foe within range who successfully deals the astral dreadnought 30 damage or more in a single turn. Because this effect is only temporary, lasting a round at most, I’m not going to be a softie and give it an easier criterion to meet. Two legendary actions is a high price to pay.

When to use Claw is easy: You hurt the astral dreadnought, it hurts you back. This legendary action is strictly retaliatory, used against foes who deal more than 0 damage but less than 30, or when the astral dreadnought doesn’t have 2 legendary actions to spend.

That leaves the question of how the astral dreadnought retreats if and when it must. Because it’s so fast (I’m counting only its flying speed here—why does a creature bound to the astral plane even have a non-flying speed?) and will always be outnumbered, its best option is to Disengage. But is it smart enough to know how to do that, even instinctively? I think not. The next-best choice, because of its high Armor Class, is Dodge; therefore, that’s what it does as it retreats.

Next: TBD. I may go back and mop up monsters I’ve missed from Volo’s Guide to Monsters and Mordenkainen’s, or I may crack open Eberron: Rising From the Last War, or I may address a pair of omissions from both the blog and the book: the scout and the spy. We’ll see what kind of mood I’m in next week.

16 thoughts on “Astral Dreadnought Tactics

  1. You say it’ll bite if a claw reduces a creature to below 34; But is wisdom by itself, without intelligence, enough to know when that happens? Also, why 34? Bite deals an average of 36.5.

    I’d also mention, BTW, that it’s practically immune to visual illusions; If it can see the illusion, it’s within the cone.

      1. Alright, 34 seems right then.
        But I don’t think with 14 Wis and 5 Int the Dreadnought would be able to distinguish between an opponent that has 32 hp to one that has 38.

        1. Yeah, I went back and forth on that, and finally handwaved it by deciding that it had an instinctual sense of when its prey was weakened enough for it to go in for the kill. If you think that’s too much of a reach, then it probably shouldn’t Bite at all until the target is already down to 0 hp; any other threshold is vulnerable to the same criticism.

  2. Thanks for this. Been salivating over this thing since it appeared on… MotP?

    Anyway. What’s your opinion of the Silver Cord mechanics? Specifically instant death.

    My opinion is that mechanics like this are awful, just really bad. “Random Death Touch” mechanics mess up the connection between player decisions and outcomes. Either players respond rationally to expected outcomes (ie. something like the average), leaving them subject to the occasional RDT having nothing to do with the overall difficulty of the encounter, or they respond to the possibility of the RDT (assuming they know) and waste resources overreacting to mostly average attacks.

    It also feels horrible. “I… died? I had full hit points! Where’s my saving throw! What do you mean, there’s no plausible counterplay? Seriously, it’s on crits, which auto-hit?”

    It belongs in the distant past of permanent level and Ability drain (much less terrible, but still terrible, mechanics, removed for all the same reasons that Silver Cord should be).

    The problem with RDT becomes clearer once we try some solutions. For example, we could make the RDTs less frequent, hoping to minimise the problem. However this INCREASES the difference between expected outcome and worst-case. It happens less often, but is more egregious.

    Ironically, the way to make RDT part of a system is to make it MORE common, moving the expected outcome closer to instant death, and therefore more sensible and rewarding to plan against.

    Assuming, of course, that the game in question doesn’t feel awful with instant death mechanics – I don’t think DnD is such a game, because we’re encouraged to invest in each of our characters over many levels (especially if we’re high level enough to be in the Astral).

    I think there’s some tiny place in DnD for instant death. That place is on weapons and entities that:

    – clearly have that power. A vorpal blade should be clearly identifiable. Escape should always be an option.
    – preferably never target PCs (eg. are wielded by them).
    – require multiple rolls to pull off. A hit followed by a saving throw for example. This means that the rare threat of ID becomes a moment of suspense, and the saving throw gives a sense of control (illusory, but then this is all about how badfeel RDT is).
    – could plausibly achieve the kill regardless within a short time. For example, Power Word Kill, as you’ve noted, is often in balance with other options to get through those last 100 hp.
    – related, it shouldn’t allow triumph over arbitrarily powerful opponents. Seems odd, like, maybe it would be nice to go after a powerful enemy just on the hope of getting one crit. But that’s suicidal thinking, illustrating my problem with planning on expected outcomes vs. extreme scenarios.

    DnD also has this level-appropriate encounter philosophy, and I think RDT is basically incompatible with that.

    So. That’s my opinion. It’s shared by at least MtG designers and Exalted designers (2nd ed., as the 3e solution is to get rid of it).

    If the Astral Dreadnought lacked this power, would that affect the CR? My analysis above would suggest that it shouldn’t, because a 5% chance event has a very low weighting – the core of the problem. I think Instant Death isn’t even in the table of factors for calculating CR, not should it be.

    Is there something you might replace this with? I know you don’t usually comment on house rules.

    But for example, the traveler could be stranded in the Astral, or dumped back into their physical body.

    I’ve had three opportunities to visit the Astral, all of which I’ve talked the party out of. Sorry to those DMs, I don’t like to upset your plans, but my PCs had the relevant knowledge (one was even Gith! He would know). That’s what happens when players plan on the worst case, and it’s detrimental imo.

    1. Oh there’s another criterion for including RDT, implied in the others: it shouldn’t produce effects wildly disproportionate relative to other effects and options. Like, if it triggers on crits, and those crits would do most of the damage towards a fatality just on their own (and we can do this math because of CR. Does this maybe apply in the case of the Dreadnought?). It brings the extreme scenario closer to the expected one.

    2. Instant death is a trifle when you’ve got the 9th lvl spells to cast astral projection. And you can also get to the astral by other means (I’ve never understood the point of Projection when you can Planeshift there), meaning you don’t even have a silver cord.

      A 5% Instakill on a CR 20 creature? hardly a problem big enough to remove; for players that level it mostly just adds a bit of extra thrill from the risk (even if they die- character death makes for a good story, assuming the players are adult and don’t act childishly over it).

      1. If you read the section on planar travel in the DMG, it’s pretty easy to restrict or limit which planes characters can plane shift to.

        Obtaining a tuning fork attuned to the astral or deep ethereal planes should prove difficult if at all possible, and might make for the objective of a high-level campaign.

        The astral and deep ethereal planes permit travel to all other planes, presumably even otherwise impossible to access demiplanes and extraplanar spaces appear a pool’s of swirling color.

        And I agree, an instakill attack is all but necessary to make monsters threatening to level 17+ characters. And it’s not like players at that level will have much trouble reviving their fallen friends.

    3. The Silver Cord is only a factor if you arrive in the Astral Plane as a result of the Astral Projection spell. If you plane shifted there, you have no cord.

      The problem with Astral Projection is that the game seems to assume that its job is to give players a mechanically interesting way to travel to the outer planes through gates in the Astral Plane. The problem is that the Astral Projection spell is worse than Plane Shift in literally every way.

      It takes ten times longer to cast, it has a higher gold cost, it only works on willing creatures, it’s a 9th level spell, fewer classes can cast it, it can only transport you to one Plane and it has special rules that are clearly worse then the game’s normal death mechanics. It has a ten foot range instead of touch, but given that it takes an hour to cast, you aren’t using it in an emergency.

      I can only see it being useful as a spell scroll given to a party which can’t plane shift and needs to get to an outer plane in a hurry. By the time you can actually cast AP, you can easily PS.

      The DMG claims that high level characters might travel via Astral Projection in order to be unkillable in the outer plane they travel to, but the actual text of the spell indicates that you regain your physical body if you leave the Astral Plane.

      1. What’s interesting is while the silver cord mechanic can kill, it emphasises the fact that you aren’t in the Astral Plane to fight, especially a dreadnought. If you anticipate a fight with something that cuts cords, you should use Plane Shift or Gate but there are far more Celestials, Fiends, and Fey that’ll be hostile than creatures that can cut a silver cord. Githyanki are your biggest concern, yet there’s only 2 types that can cut a cord.

        It’s also shown that if you move to another plane, your physical body comes with you but NOT forced to combine. It just allows you to rejoin your body. Find a good enough place to hide your physical body and your spiritual one has nothing to fear unless the githyanki followed.

        It’s better to get on friendly terms with Githyanki somehow anyways, though. How to do that against an evil militaristic raider group that hates all races? I don’t know. You could agree to bring the head of an influential Mindflayer or Githzerai. Though, you have access to 9th-level spells so you could try an 8th-level spell or something.

        The DMG also mentions that attuning the 250 gp fork. It assumes you’re crafting it yourself which would take 50 days and needs to find a way to get the frequency of the plane or a sigil sequence to a set circle which is supposedly even harder to come by. I’d say it’s an interesting design to trap the secret of the Astral Plane’s frequency behind an ancient Red Dragon’s mind and the players would either have to find a way to get the dragon to reveal its secret (which they probably won’t willingly) or wait until someone can cast Astral Projection (which some parties are too impatient to do.) You could also request a wizard cast Astral Projection which needs no knowledge, only access to the spell.

    4. You should have just talked the party into buying adamantine armor. Literally just an uncommon magic item entirely removes the cord cutting mechanic. Not a lot of investment required if you were going to metagame your party into not going; just metagame them into buying protective gear instead.

      It’s really not an issue. With relevant knowledge comes ways to plan around it. If they’re willing to invest in doing that, you’ve got the makings of a fun montage quest to build up the import of the big trip. If they’re not, they can’t whine if the worst comes to pass. Even in an actual fight scenario you can just take the Dodge action nonstop while fleeing and it’ll never happen. This molehill’s not a mountain, but if you kick at it repeatedly and then say you stubbed your toe I guess it can seem so.

  3. The astral dreadnought has a non-flying speed in case it needs to move on or into the body of a dead god or similar mass of “stuff” on the astral plane, presumably to get at prey to eat. If space restrictions make it squeeze, it’s gonna crawwwwl. This also presents a way for a party to escape it (“Quick! Into the bowels of that dead god!”).

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