Swarm Druid, how would you do it?

[Arkhios]

My better half was oddly extatic about the idea of a druid turning into a swarm - which actually was an option in 4th edition (which is where she found it - or rather, I told about it) but she prefers 5th edition due to personal reasons, as do I.

If you were to 'brew something similar, how would you do it?

A friend suggested a few pointers I found compelling:

"I’d say 4th level at the earliest, and you don’t get swimming forms at that level. Then at 8th you have to pick whether you want flying or swimming forms.

Since being a swarm does provide its own special forms of mobility."

and...

"Also, the druid would probably be slightly touched in the head. Splitting your consciousness in that way can’t be healthy for the psyche.

Maybe even an extra flaw, something like “I have trouble seeing people as separate individuals.” ...Or something else appropriate."

[Reaver25]

Swarm Druid would be interesting.
I like the idea of not being able to at 4th. But I wouldn't limit the Druid to only swimming OR flying at 8, that's not normally a restriction.
Perhaps Druid can see from all of the different creatures in the swarm but it's a more basic vision, so a negative modifier to Perception or Investigation?

[The Cats]

Like this:

CIRCLE OF THE SWARM
SWARM FORM
When you choose this circle at 2nd level, you gain the ability to wild shape into swarms. At 2nd level you can wild shape into a swarm of rats, beetles, centipedes, or spiders. At 4th level you can also wild shape into a swarm of quippers. At 8th level you can also wild shape into a swarm of bats, ravens or wasps.
Because a wild shaped druid swarm is controlled by a guiding mind it has the following differences from the statistics presented in the Monster Manual.

• The creatures in the swarm can better coordinate their attacks. The swarm uses your Druid spell attack bonus as the attack bonus for all of its attacks and adds your wisdom modifier to any damage rolls.
• Because the creatures share a single mind, the swarm is not immune to the charmed or frightened condition. Because your consciousness is spread across so many entities, however, you do have advantage on saving throws against charm and fear effects.
• As your power grows, so too does the number of creatures you can hold in your swarm. When you enter swarm form, the swarm’s maximum and current hit points are increased by a number equal to your druid level times 3. If the swarm’s hit points are increased to 40 or more this way, it becomes a Large swarm of Tiny beasts and takes up a 10-foot square. If its hit points are ever reduced below 40, its size decreases and it becomes a Medium swarm of Tiny beasts and takes up a 5-foot square.

SUDDEN SWARM
Starting at 2nd level, you can enter your swarm form in response to danger. When a creature targets you with an attack, as long as you are not surprised, you can use your reaction to wild shape into a swarm form and move up to the swarm’s speed toward the attacker. If the attack hits, the damage is dealt to the swarm form. You must choose to use this ability before you know the result of the attack roll.

INFESTATION
Starting at 6th level, your swarm forms become supernaturally horrifying and creatures that find themselves infested with your swarm are shaken to their core. Any hostile creature that starts its turn sharing a space with you while you are in swarm form must make a Wisdom saving throw against your Spell DC or be frightened by you until the start of their next turn.

DISEASED BITE
At 10th level, you gain the ability to infect your enemies with Magical Diseases. When you hit a creature with a swarm’s bites or beaks attack, you can cast a Magical Disease spell as a bonus action. When you cast a Magical Disease spell this way you can only target the creature you hit with the attack.

At 18th level you can choose to cast a Magical Disease spell as an action without requiring an attack. If you cast a Magical Disease spell this way and it allows you to target more than one creature, you can targets as many creatures that you are sharing a space with as the spell allows.

Magical Diseases: You can cast certain spells as Magical Diseases using your Diseased Bite ability. When a spell is cast as a Magical Disease it has the following properties:
• It is considered a disease
• It’s range is reduced to touch if it was longer
• It does not require any components
• If the target of the spell is frightened of you it has disadvantage on saving throws to resist the spell

Casting a spell as a magical disease otherwise follows all the normal rules for spells and spellcasting.

Magical Diseases Known: At 10th level you learn to cast one cantrip and two spells of first level or greater from the Magical Disease spell list. You learn to cast one more spell as a Magical Disease at 12th, 14th, 16th, 18th and 20th level. Each of these spells must be of a level for which you have spell slots. Spell you can cast as Magical Diseases are considered Druid spells for you, even if they don’t appear on the Druid spell list. You always have these spells prepared and they don’t count against the number of spells you can prepare each day but can only cast them as Magical Diseases unless you also learn or prepare them from some other source.

PARTIAL DISSOLUTION
At 14th level you gain a finer degree of control over your swarm transformations. As an action you can have a small part of your body transform into a single bat, beetle, centipede, quipper, rat, raven, spider, or wasp. You are only able to maintain these creatures for a short while and they will die ten minutes after their creation. When you use this ability your maximum hit points are reduced by five. Each time after the first, the maximum hitpoint reduction increases by five. This resets after a long rest. You cannot use this ability while wildshaped.

A creature created with this ability can re-merge with you by touching you as an action. When it does so, you regain the maximum hitpoints you lost from creating it, but you are not healed for the same amount, and you learn everything it experienced while it existed. If the creature dies before re-merging with you, your maximum hit points will remain decreased until you complete a long rest.

Creatures made using this ability acts independently of you but you can give any number of them a simple command as an action, which they will obey. If you do not command them they will defend themselves from hostile creatures but otherwise take no actions.

MAGICAL DISEASE SPELLS

CANTRIPS (0 LEVEL)
Infestation (XgtE)
Poison Spray

1ST LEVEL
Bane
Cause Fear (XgtE)
Sleep
Tasha’s Hideous Laughter

2ND LEVEL
Blindness/Deafness
Hold Person
Mind Spike (XgtE)

3RD LEVEL
Bestow Curse
Enemies Abound (XgtE)
Slow

4TH LEVEL
Blight
Confusion

5TH LEVEL
Hold Monster
Contagion

6TH LEVEL
Flesh to Stone
Harm

7TH LEVEL
Power Word Pain (XgtE)

8TH LEVEL
Feeblemind

9TH LEVEL
Psychic Scream (XgtE)


It's a subclass similar to Moon in that it uses wildshape in combat, but different in that it is much more focused on battlefield control than on tanking and DPS.

[HandofBlades]

For a swarm Druid I would probably focus more on damage reduction abilities and perhaps even focus on some new interesting play style options.

I would make wild shape similar to the moon Druid where it can choose higher level swarms to wild shape into. I would also aim for a feature that focuses on mental advantage when it comes to wisdom and INT saving throws or perhaps profiency in another save when higher level.

As for a level six ability I would have the swarm wildshape happen almost without thinking when attacked and reduce damage till the start of your next turn but uses a wildshape up as a reaction to being hit.

At ten I would have something along the lines of swarming defense. Small bugs and other creature follow you around and you get an aura of let's say 30 feet and any time an ally or you are hit with an attack reduce the damage by say your wisdom modifier.

The swarm never dies. At 14 when a blow would reduce you to zero it instead reduces you to one hit point recharge on a short rest. Also at this level i would give them defend the colony. When you are first damaged by an enemy in combat when wild shaped into a swarm you gain a bonus to damage equal to your remaining hit dice. Showing the hit dice as how much of the swarm remains. Could be cool could be broken.

[Strangways]

My better half was oddly extatic about the idea of a druid turning into a swarm - which actually was an option in 4th edition (which is where she found it - or rather, I told about it) but she prefers 5th edition due to personal reasons, as do I.

If you were to 'brew something similar, how would you do it?

A friend suggested a few pointers I found compelling:

"I’d say 4th level at the earliest, and you don’t get swimming forms at that level. Then at 8th you have to pick whether you want flying or swimming forms.

Since being a swarm does provide its own special forms of mobility."

and...

"Also, the druid would probably be slightly touched in the head. Splitting your consciousness in that way can’t be healthy for the psyche.

Maybe even an extra flaw, something like “I have trouble seeing people as separate individuals.” ...Or something else appropriate."

I'm guessing that will be implemented by way of a Druid-specific spell at some point, something like a polymorph self spell.

[Arkhios]

I'm guessing that will be implemented by way of a Druid-specific spell at some point, something like a polymorph self spell.

In the meantime, I believe the most elegant way to deal with this might not be a whole new Circle, but instead only a new option for Wild Shape.

Alternatively, I had a thought that this feature might work as a 1/short rest Eldritch Invocation specifically for the Great Old One warlock (due to the implication of it's weird and potentially damaging to one's psyche, which seems appropriate for Great Old Ones).
Essentially it would require, say, 5th level in warlock and work more or less like the Druid's Wild Shape but would be limited to changing into swarms only.

[hymer]

If someone really badly wanted it, I think I'd keep it simple. Since I'd let the druid turn into any of the individual beasts, the ability to squeeze through tiny places won't make much of a difference. But all the resistances and immunities of swarms make them more attractive than regular wild shapes. So I'd probably have them cost two wild shape charges, and I'd make some swarms for the missing CRs. Just making the swarms bigger should make a simple concept, and explain more hp and stronger and more/stronger attacks.

[Beelzebubba]

This is spitballing, but I could also see a Circle of the Land version, but themed to use bugs and swarms of things as the special effects for the domain spells.

Cantrip at 2nd level:
Infestation

Domain spells:

L3
Blur - form is occluded by swarming bugs
Dust Devil - flying insects

L5
Gaseous Form - swarming gnats
Fly - hauled along by fey crows

L7
Blight - fey mosquitos sucking their blood
(option A) Contagion - fey mosquitos transmitting disease
(option B) Hold Monster - fey swarm of something covers them, preventing movement

L9
Insect Plague - duh
Mislead - double is a bunch of bugs?

[Beechgnome]

Have a look at my Circle of the Many in my sig. It's a bit complicated... but I've enjoyed playing it as a DM.

[tieren]

I don't see a problem just allowing it for a land or shepherd druid. for a moon druid I would just restrict swarms to the CR's that would normally only be available to a land druid.

The kicker is going to be sticking to the movement restrictions until they are the appropriate levels, so at 2 you can become a swarm of rats or snakes, but not much else. Won't be able to do bats or flying insects until at least level 8 by which there are just better things to turn into most of the time.

I would also make them keep the whole swarm in one space all of the time, no dispersing and reforming nonsense.

[Vogie]

There is a Vermin Lord on Middle Finger of Vecna (http://mfov.magehandpress.com/2016/02/vermin-lord.html) that would work.

If UA is allowed You could also go Fiend Warlock 2 / Circle of Spores Druid X.

Fiend Warlock - That'll give you the Cloak of Baalzebul invocation, which is a swarm of flies and another invocation that you could thematically show your swarm - such as Misty Visions, Devil's Sight, Beast Speech, et cetera. Your sword burst and mage hand cantrips could be refluffed as you sending out bugs to move or hurt things, can regrow your level 1 warlock spells on a short rest, specifically Hex, where the disadvantage and damage can be fluffed as being attacked by small vermin. The Dark One's Blessing pseudo-healing works well alongside the Symbiotic Entity.

Circle of Spores - you can just refluff as using swarms of insects instead of fungal spores, which also gives you other options than Wild shape. Symbiotic Entity and Fungal Body could also fluff-fit as the Swarm druid being an avatar made of a swarm rather than a normal PC.

Since Druid circles stop giving bonuses at level 14, you also have the ability to add more warlock abilities beyond that. At any point, you can go a single extra warlock level to add a vermin familiar (bat, crab, frog, lizard, poisonous snake, rat, or spider) or being able to manifest weapons from nowhere (via pact of the blade) give you non-spell or non-wild-shape-oriented way to fight.

[Talionis]

Alternatively, I had a thought that this feature might work as a 1/short rest Eldritch Invocation specifically for the Great Old One warlock (due to the implication of it's weird and potentially damaging to one's psyche, which seems appropriate for Great Old Ones).
Essentially it would require, say, 5th level in warlock and work more or less like the Druid's Wild Shape but would be limited to changing into swarms only.

I could get behind this as an invocation if you allow Homebrew. I like the idea of them being able to cast this as an reaction. I'm not sure if its once per long rest or short rest and I'm not sure on the level or duration.

But thematically, I could see this very well as Bats, Scorpions, Ants, Spiders, Moths, Snakes, etc. Anything fairly creepy. Because you could do this with a spell almost as easy as an Invocation.

My one bone to pick with Warlocks is lack of spell selection.