Heyho community,

after trying to create an interesting and logical Fairy race, I came upon some physic details which play quite well into the D&D-dynamics and I wanted to share some of my thoughts.

(Disclaimer: My native language is German, hence the strange build of sentences and the occasional composed nouns. Please be free to point out any grammatical errors and misused words.)

Disclaimer #2: My intelligence stat fluctuates between 16 on great days and 8 on Mondays. I received mayor inspiration from Shadiversity, CaptDeathCap, the original UA Fairy from wizards of the coast and, of course, Terry Pratchett.

Now, to the topic:

Fairies are tiny creatures, I imagine about 20 - 15 cm large (8 to 6 inches for the Imperials). An appropriate comparison in size would be a blackbird, maybe, but I think a hummingbird would work, too. Fairies can squeeze through passages up to 2 x 2 Inches (roughly 5 x 5 cm).

They are exceptionally fast, with 30 ft. of flight movement. While they are flying, they have disadvantage against strength saving throws to avoid being pushed or pulled. They ignore ground tremors and have advantage against being grappled. Ascending (Vertical movement without horizontal one) costs double and can be treated like difficult terrain. Grounded, every crack in the ground becomes a chasm, and every pebble a boulder. But the muscle - weight - ratio works in their favor (imagine a child doing a pull-up without problems, but an untrained grown-up? Not so much), hence a movement speed of 10 ft. Strength (Athletics) checks are tricky, because fairies should be trained jumper when they can fly, and their reduced weight makes climbing or holding on to something quite easy. Please propose a possible solution to this problem.

Although they are in relation for their size very strong (like an ant), they shouldn't fly in medium or heavy armor, the metal being useless dead-weight. You could make your Fairy a flying tin can (is this redundant?), but better give them a razor blade which is as long as they are (that scales nicely with certain anime and gaming characters - looking at you, Cloud). Shields are interesting. The badge of a watch might be enough to cover the entire body, best made from aluminum or other light materials (no glass, obviously). Ranged weapons don't work for Fairies because the projectile velocity scales with the absolute strength of the wielder. Although they can lift maybe objects twice their size, they can't draw a human longbow. Arrows of Fairy-scaled ranged weapons wouldn't fly far, and the impact would be like throwing toothpicks. Annoying in certain areas, but mostly harmless. No ranged weapons for Fairies.
But look at it like this: they are the projectiles.

Imagine fighting a giant in full plate armor (ridiculous because it/he/she wouldn't be able to move). Against other monstrous creatures, the giant is perfectly covered, but we puny humans could take advantage of the large gaps between the plates, e.g., we could reach the Achilles tendon, blood vessels at inner tights, wrists, throat and neck, the sternum, heck, even eyes and ears of the giant is thrown to its back. Loosening the leather straps which hold the armor in place, crawl at or inside limbs... Now imagine that you can fly and hover...
An adequate modelling in D&D would be that fairies ignore the AC bonus (what's the correct plural? Boni? Bonusse? Bonuus?) of medium and heavy armor. Shields still apply.

Weapon damage is interesting, because, I think, Fairies can deal massive wounds with slicing utensils such as daggers, razor blades, butter knifes, glass shards, box cutters, scissor blades etc. since their precision and edge alignment must be over the top good, but only normal or less piercing damage (nails, needles, toothpicks, pens, thorns...) because of the impact strength and actual possible wound size. Blunt force will never be a Fairy's first choice of attack. Try beating someone to death with a walnut. Max damage 1, if any.
I would double the damage of slashing weapons, halve piercing, and set bludgeoning to 1.
Scaling weapon dice to Fairy size isn't necessary. A d8 for longswords stays a d8 for a scissor blade, but a greater versatility dice doesn't make sense, same for reach. The heavy property is inconsequential; if the Fairy is proficient with it, it can use it. I'm open for suggestions regarding lances.
Without question, all piercing and slashing weapons should be wielded with dexterity instead of strength.

But what about receiving damage? You could always halve the HP of your Fairy, but I wouldn't recommend that. A lv. 1 Fairy wizzard (who gets the reference?) or sorcerer with a constitution of 12 (+1) could be viciously mocked to death with one unlucky roll of 4. Instead, The GM could describe weapon damage as only "grazing" due to the Fairy's great mobility, or you could use HP as "luck points" (no wounds or bloodshed until half HP, deadly wound to 0 HP, obliterated when instadeath -losing HP means coming closer to a critical wound).
Another immersing effect of being hit by a weapon could be that the Fairy must succeed on a Strength saving throw (with disadvantage if its flying), DC damage, or be pushed back from the attacker an amount of foot equal to the damage, without provoking opportunity attacks. For example, the Fairy is hit by a morningstar of a bugbear, 11 (2d8+2) piercing damage. It must succeed on a Str SR DC 11 with disadvantage or be pushed 11 ft. (2 squares) away from the bugbear, but it doesn't provoke any opportunity attacks (except maybe with sentinel or something like that).

What if it lands in the space of another creature? Well, it's tiny size allows the Fairy to share space with creatures of any size. If the creature is medium or larger, it provides tree-quarters-cover for the Fairy to all creatures, except of course, to the one which provides the cover. I had the idea that the Fairy must share space with a creature to attack, due to its short reach.
Another question: does nonmagical difficult terrain provide cover for a Fairy?

The cubic law works in the Fairy' favor when it comes to carry weight and being able to withstand extreme heat like in a desert. A larger surface with less volume means more heat loss, hence a lower risk of overheating. Consequentially, Fairies make saving throws against hot conditions with advantage. The cold on the contrary, like on mountain tops, in arctic wastelands or the depths of the sea, is twice as dangerous. Distributing heat in your extremities becomes difficult if the diameter of said limb is maybe half a square centimeter or less. Fairies make saving throws to withstand cold conditions with disadvantage.

Weather - Ugh! Save to say: if the raindrops falling heavily from the sky are as big as your head, no sane Fairy will be caught in the air. The same applies to heavy fog, snow, or wind speeds above a stiff breeze. Considering that every large leaf is adequate cover, this is not a deal breaker. Nonetheless, a Fairy will be careful not to holiday in a rain forest.

Living expenses are funny because Fairies need so much less than "normal" humanoids. They don't have to pay rent if they can sleep in a glove above a fireplace mantelpiece, travel on the shoulder of any medium creature and bathe in a cold cup of tea. Their supplies of medicines, poisons and ingredients come in thimbles. Meals, I imagine, are smaller but more frequent. To transform enough energy to stay warm and fly, Fairies must eat constantly and have a crazy metabolism, congruent to a bird’s. For the sake of gameplay: a healing or any other potion works the same for medium sized creatures as it does for Fairies. They must drink the full vial, even if it's larger than themselves. 
Magical equipment (especially weapons and armor), if they don't resize automatically, must be shrunk by artificers or magicians for an extra price and can't be used before.
Nonmagical equipment like custom weapons and armor should cost roughly the same: less material, but more detailed work cross each other out.

That are my thoughts towards small-people-physics, easily adjusted to any tiny size who wishes to pick up weapon skills and murder innocent bandits. If they appear to be in favor of Fairies, here is a major weakness: they are deathly afraid of fire. A torch carried is enough to keep easily flammable wings away from the weary traveler. But pray to the Gods that it doesn’t go out…

Another thought was raising the maximum dexterity stat of Fairies to 30. It seems fitting but is probably easily exploited (exploitable?).

TL: DR Fairies

- creature type: fey

- size: tiny

- speed: 10 ft.

- fairy flight: 30 ft. flight, no medium or heavy armor, disadv. Str ST ag. Being pushed or pulled, ignore ground tremors, adv. Dex ST ag. Being grappled, treat ascending as difficult terrain

- toothpick-arms: can’t use ranged weapons

- altered perspective: ignore enemy AC bonus of medium or heavy armor, shields still apply

- relative weight: deals double slashing dmg., half piercing dmg., always 1 bludgeoning dmg., ignore reach, heavy and versatility properties, can use Dex instead of Str for attack and dmg. rolls

- involuntary projectile: after being hit by weapon Str ST (DC dmg.), else pushback foot equal to received dmg.

- peekaboo: can share space with creatures of any size, must share space for attacks, medium creatures and larger provide ¾ cover to all other creatures except providing one

- cubic law: adv. Checks to withstand heat, disadv. Checks to withstand cold

- weathurgh: no flying in rain, heavy fog, snow, and storms

- living the high life: half living expenses, not food, magical equipment must be resized, custom weapons/armor cost the same

Optional rules:

- highly flammable: can’t come closer than 5 ft. to open flames

- the sky is the limit: max. Dex stat raised to 30, edit: 24

A very detailed race, to be sure. Probably too detailed for a lazy person such as myself to decide on its balance.

Quote from Et_Henta_Cala>>

<snip>

That are my thoughts towards small-people-physics, easily adjusted to any tiny size who wishes to pick up weapon skills and murder innocent bandits. If they appear to be in favor of Fairies, here is a major weakness: they are deathly afraid of fire. A torch carried is enough to keep easily flammable wings away from the weary traveler. But pray to the Gods that it doesn’t go out…

<snip>

Way too complicated and unnecessarily detailed dude! You have clearly put a lot of effort and thought into this, but the racial design you have made is more like a class than a race.

 Let's tidy this up a bit so that the race doesn't dominate the player's gameplay, and isn't crazily confusing.

• Creature type: fey
• Racial Bonus: +2 Dexterity
• Size: tiny
• Speed: 10 ft.
• Fairy flight: Fairies have a 30 ft. flight speed whilst not wearing medium or heavy armor.
• Tiny creature: Your maximum strength score is 10, and your maximum Dexterity score is 24. Keeping it simple. 30 is too high for a max stat, and nobody wants musclebound fairies. 
• toothpick-arms: can’t use ranged weapon Why not? They could use blowpipes, nets etc.
• Tiny weapons: When a fairy touches a weapon, armor or magical item continuously for 1 minute, it shrinks so that the fairy can wield it. It retains its new size until the fairy dies. This allows them to use magical weapons that they find.
• - altered perspective: ignore enemy AC bonus of medium or heavy armor, shields still apply Way too complicated
• - relative weight: deals double slashing dmg., half piercing dmg., always 1 bludgeoning dmg., ignore reach, heavy and versatility properties, can use Dex instead of Str for attack and dmg. rolls This is silly for a racial trait (and hugely overpowered), and makes no sense. You can't have a fairy dealing double the damage that a Bugbear barbarian does.
• - involuntary projectile: after being hit by weapon Str ST (DC dmg.), else pushback foot equal to received dmg. Needlessly complicated
• - peekaboo: can share space with creatures of any size, must share space for attacks, medium creatures and larger provide ¾ cover to all other creatures except providing one While I understand the reasoning, this makes battlemaps problematic
• - cubic law: adv. Checks to withstand heat, disadv. Checks to withstand cold There is no reason for a fairy to have this benefit
• - weathurgh: no flying in rain, heavy fog, snow, and storms Due to 10ft move speed, makes the fairy useless in any bad weather
• - living the high life: half living expenses, not food, magical equipment must be resized, custom weapons/armor cost the same
• Optional rules:
• - highly flammable: can’t come closer than 5 ft. to open flames
• - the sky is the limit: max. Dex stat raised to 30

This is a much simpler, less overpowered loadout that keeps character class more important than racial bonuses, and avoids needless complications.

I realize that you put a lot of thought and effort into this but not all of it is needed.

The game is balanced around 10 being the average for any stat for any PC. HP are the same issue - given the same CON and HP rolls, a Gnome Fighter will have the same HP as a Goliath Fighter at the same level, yet both are vastly different in size. Their stats could be the same with both having 20 STR.

The majority of the things are flavoring for what seems reasonable.

For weapons rather than making up new rules, use the existing ones. Something like, they can't use Heavy, Two-handed,  or Versatile weapons. They can only use Light weapons one handed and other weapons are two-handed for them. Saying their weapons only do minimal damage or that they can't use ranged weapons is handicapping the race for no reason. Letting them use normal weapons is balanced for the sake of game play.

Giving them a walking speed of 10 is not needed as most other races are 25+, Let them have the 25 it isn't game breaking because every other race is the same or better. 30 speed flight is fine as Aarakocra have 50.

Realistically armor and equipment prices and weights would be affected, but price can stay the same as custom work has a price. But like the above example, a suit of plate armor would weigh and cost the same for the Gnome and the Goliath.

In the end, you want to be able to maintain a sense of balance compared to other races. 

The original purpose of this post wasn't to create a fairy race per sei, but to reevaluate physics (and economy) for tiny creatures.

And I admit, it makes playing a Fairy kinda awkward. Sometimes, I value realism higher than pure game play.

Also, I really like to differentiate between different weapon damage types. If bludgeoning is equal to piercing is equal to slashing, why do you do it in the first place? Role play? What if I tell you, that you can stab somebody with a sword and slice somebody with a dagger? Shocking, Isn't it 😉

I stand to my point: no ranged weapons for Fairies. How far could a songbird throw a rock? What poundage could a mouse realistically draw? Ranged weapons which don’t rely on strength like blowguns or firearms should work.

And they themselves can be thrown by any creature of average strength.

Also also, read my reasoning for cubic law and weather effects, it’s highlighted.

But thank you all for the valuable feedback

Quote from Et_Henta_Cala >>

Also, I really like to differentiate between different weapon damage types. If bludgeoning is equal to piercing is equal to slashing, why do you do it in the first place? Role play? What if I tell you, that you can stab somebody with a sword and slice somebody with a dagger? Shocking, Isn't it 😉

I stand to my point: no ranged weapons for Fairies. How far could a songbird throw a rock? What poundage could a mouse realistically draw? Ranged weapons which don’t rely on strength like blowguns or firearms should work.

 

 How can a songbird have the muscle mass to cut through a human's skin, even with a dagger? Even if they manage it, they won't penetrate cloth, leather, let alone iron.

The ratel or honey badger has skin that is loose and thick enough to withstand a lot of conventional attacks:

"The skin is also tough enough to resist several machete blows. The only sure way of killing them quickly is through a blow to the skull with a club or a shot to the head with a gun, as their skin is almost impervious to arrows and spears."

Compared to a fairy, any humanoid's skin is too thick for them to cut with a dagger. If you want to implement real world physics to this level (which I really don't advise) then it should be impossible to efficiently wound any creature 2 sizes larger than you with handheld weapons.

If that is the case then I would consider using the rules for swarms like Swarm of Ravens representing their ability to only affect creatures larger than them if they fight en mass.

The process of cutting is the balance of pressure and the amount of material moved away from the cut. Fairies can't apply a lot of pressure, but they have the opportunity (by getting close to the enemy) to attack with substantially sharper knifes such as scalpels. Have you ever sliced meat with a sharp razor blade (or skin with a fresh scalpel)? You don't have to press hard to make deep cuts.

Fairies have the reflexes and precision to find cuts between armor and sensitive areas with large blood vessels to deal devastating blood. Most adventures aren't covered in metal plates from head to toe (try moving) and don't seem to wear helmets with visors (try seeing something in dungeons).

The throat is one of the most vulnerable places on most creatures, and eyes even more so.

Of course, if the skin is leathery thick or covered with scales (aka "natural armor"), they won't do much. But so won't other races.

Quote from Et_Henta_Cala >>

The process of cutting is the balance of pressure and the amount of material moved away from the cut. Fairies can't apply a lot of pressure, but they have the opportunity (by getting close to the enemy) to attack with substantially sharper knifes such as scalpels. Have you ever sliced meat with a sharp razor blade (or skin with a fresh scalpel)? You don't have to press hard to make deep cuts.

 

Have you ever hit a hanging pig carcass with a longsword? You can cut straight through leathery skin, flesh and even the spine in one blow. A fairy attack even with an ultra-fine blade would do negligible damage to a medium sized humanoid. If we want to aim for real world physics, then yes, fairies can deal shaving cut damage. But shaving cuts don't equate to a single hit point, while a longsword blow will take your head off.

Fairies best attacking method would be to fly at the target with a long thin weapon - a knitting needle for instance - and essentially make themselves into a bullet. Slashing with a knife is very painful, but it's actually pretty difficult to kill someone by slashing them with it (you'd be surprised how hard it is to get through a mammal's throat tissue with a knife). Conversely, a thrust into a vital organ is commonly fatal and can be performed by a very physically weak creature quite easily.