Pretending that this is a class based system for now.

Artifice

Power Sources

Power sources:

• Energist: rare, always-on
• Power cell: x/day

Energists have a type:

• Air
• Earth
• Fire
• Water
• Aether
• Nether

You can't have all 6. Air<->Earth and Fire<->Water oppose each other, as do Aether<->Nether.

Aether can fill in for any base element, without causing enmity with its opposite. There are also Aether-specific devices.

Energists have a rank from 1-5.

Physics Stuff

For now, let's assume power cells are full of phlogiston, which is basically diesel fuel.

The energy density of diesel fuel is 44 MJ/kg.

The 9x19mm Parabellum bullet is a very common pistol/SMG cartridge. A typical 9mm has a bullet mass of about 8g, fired at a velocity of 360-430 m/s. The volume of the fuel portion of the cartridge seems to vary from 56-84 mL, so let's take the average of 70.

Let's calculate the energy of 70 mL of diesel fuel...

• diesel fuel desntiy is arond 0.85 kg/L
• 70 mL is 0.07 L and weighs 59.5 grams
• 59.5 grams of diesel has 2.618 MJ of energy

According to chatGPT, 1 kg of 25 degree C water can be heated to boiling point and vaporized by 2.5 MJ

• That could accelerate a 0.1 kg projectile to 7.1 km/s
• I don't know about those numbers, personally, so let's do our own math.

Let's try 70 mL of water. The steam pistol has a power cell "hammer" that infuses heat into the water, so the bullet itself only contains water.

• 70 mL of water weighs 0.07 kg
• Water requires 4184 J to raise 1 kg by 1 degree C
• 70 mL of water requires 293 J to raise by 1 degree, or 21,200 J to raise from 25 to 100
• 1 gram of water at 100 degrees C requires 2,260 joules to fully vaporize
• 70 grams of water at 100 degrees C requires 158,200 joules to fully vaporize
• diesel fuel's energy density is 44 MJ/kg or 44,000 joules per gram
• we need about 3.59 grams of diesel fuel to vaporize our water. Seems reasonable.
• let's try some efficiencies:

At 10% efficiency, our 158,200 joules becomes 15,820 joules.

• According to chatGPT, that'll move our 8g bullet up to 1988 m/s. Wowza.
• Also, modern bullets tend closer to 32% efficiency.

However, this is actually a ton of water. Wikipedia lied (or I misread it, you know). The best-case volume for the fuel portion of a 9x19mm Parabellum is 1.2 cubic centimeters, aka 1.2 mL of water. Let's do the math again:

• 1.2 mL water weighs 1.2 grams
• 1.2 mL water requires 5.02 J to raise by 1 degree, or 376 J to raise to 100
• 1.2 grams water at 100 degrees C requires 2260 * 1.2 = 2,712 J to fully vaporize

The problem here is that we're assuming the water's kinetic energy magically becomes bullet energy. The mechanism that gives bullets momentum is that the high-pressure gases produced by the fuel's combustion want to expand, and the bullet is free to move down the barrel, so the expanding gas pushes it as it expands. The more it expands, the lower the pressure gets. When the pressure gets too low, it can't overcome the friction of the barrel or the resistance of the air the bullet is displacing, and at a certain point, it just doesn't expand anymore due to atmospheric pressure.

Steam doesn't have anywhere near the pressure of gunpowder exhaust.

We need to work backwards. A 9x19 Parabellum bullet has, by one random Google search, about 50,000 PSI of pressure pushing it at the moment of firing. How much steam is that?

• Barrel is, let's say 5 inches long (127 mm, taken from a rough average of M1911 models), and about 9mm in diameter. Thus, its volume it about 8.08 mL (courtesy Wolfram Alpha)
• m = PV/RT (coourtesy chatGPT)
  • where m is the mass of water needed
  • P is 50k PSI or 3.447E+8 pascal
  • V is the barrel's volume, 8.08 mL or 8.08E-6 cubic meters
  • R is the ideal gas constant, 8.314 J/mol·K
  • T is the temperature in Kelvin, 100 C = 373 K
  • PV = 2,785 pascal cubic meters (kgm-1s-2 * m3 = kgm2-2 ?)
  • RT = 3101 J mol-1 K-1
  • PV/RT = 0.898 pascal cubic meters / j/mol (????), or kg m-1 s-2 m3 mol-1 K-1 K+1 ????
• So yeah, 0.898...somethings. According to chatGPT again, it's kg, because we used Pascals earlier. Let's just trust that.
• 898 grams of water, slightly less than a typical plastic bottled soda, could generate enough steam pressure to push a bullet at an equivalent acceleration to gunpowder. Of course, fitting 898 grams into a barrel with an 8 mL capacity won't be easy. Also, some quick guesstimating says that it takes something like 100-1000 times more energy to vaporize that near-liter of water than the total energy of the actual bullet, meaning some 99.99x% of the energy will become heat. The pistol will be scalding hot and it will shoot a gout of steam and boiling water, which may be a more effective weapon than the bullet itself...against both wielder and target, that is.

Sigh. It's almost like gunpowder makes sense.

• Steam Pistol: this clever tool is not, in fact, a pistol that uses steam to fire a bullet. That would be crazy. Instead, it is a cartridge-based, pin-firing, otherwise ordinary black powder pistol, with a reservoir of water, and a slot for a power cell. When the cell is activated, it boils the water, and the steam begins to do work. Once manually chambered--which also primes the power cell, after waiting a few seconds to boil water, the gun is ready to use. The gun has a "hammer", which has a sharp pin that passes through a heating element heated by the power cell. When drawn, it pulls back, and at a certain point, it snaps forward under spring pressure. The sharp pin, red-hot thanks to the power cell, penetrates the soft cartridge and ignites the powder, firing the bullet. The trigger mechanism holds the cartridge in place until fired, so it doesn't need any papers to keep it from rolling out. After the bullet is fired, a port opens to vent steam into the barrel. The steam cleans out the spent cartridge's remains, and any unburned powder. The port closes after a fraction of second, but before it fully traps the steam in the mini-boiler, it sends some into a mechanism in the handle, where a magazine containing multiple cartridges has been inserted. The steam pushes a lever down, causing another lever to push the whole stack upward, chambering another round. Thus: semi-automatic fire.
  • There are several disadvantages. The latent heat of the pin fades after a few minutes, making it unreliable at first, then reliably unable to fire bullets. Failing to fire all of the bullets in the magazine within those minutes means inevitably the gun will jam. The boiler is not built to contain limitless pressure--although it does have safety valves and will vent excess steam. If steam is vented, then firing is resumed, the reloading mechanism will fail before all bullets are fired. There is a small margin of extra water in the boiler, but not much.
  • If the weapon jams, it needs to be manually unloaded and reset. This can take anywhere from seconds to minutes.
  • When a magazine is spent, it is relatively easy to remove and replace (swift action). Similarly, priming the weapon (chambering a round and activating the power cell) takes a swift action.
  • However, the boiler is a bit more finicky. It takes a standard action to remove it, as it is tightly screwed in and has retaining pins to prevent it from unscrewing itself. If a replacement boiler is handy, another standard action can slot it in. Refilling a spent boiler takes some time, as the spring-loaded valve needs to be depressed while the boiler is submerged (or, less efficiently, held under running water). This can be done by hand, but it takes some practice. Specialized tools are preferred.
  • Once activated, the power cell burns constantly, heating the water and warming the pin. It will continue to do so until spent; there is no way to stop it. One cell has enough power to provide steam and pin heat for the few minutes the mechanism is functioning. The cell can replaced with two swift actions--one to eject the old, one to insert a new one (assuming it's already in hand).
  • Scenarios vary, but if your pistol runs out, it's going to take at least a few rounds to start firing again. So the best bet, if one is worried about running out of bullets, is to have a spare handy and loaded.
• Signal Flare: technically a powered device, but it uses less power than a typical power cell, and can be neglected. This single-use cartridge, when fired from its matching flare gun, shoots a rocket about a hundred feet in the air, leaving a trace of thick, colored smoke, which are visible a long way off in good conditions, until they disippate a few minutes later (or less in windy conditions). Various colors are available, to provide an additional dimension of communication.

Artifacts

What can you actually make?

• Tools (unpowered, or minorly powered, usable continuously)
• Consumables (powered by power cells)
• ??? (powered by energists)
  • apparatus
  • power tool

Rank 1 (Proficient)

Tools

Weapons

• Revolving Pistol: typically made in the same form factor as powder-based pistols (although many other form factors are possible), the Artificer's pistol is a much more convenient weapon. Instead of burning powder, it uses a quasi-magical material to create a burst of force. Conveniently, the bullet and this material are packaged in a common cartridge, which is held in place until fired, at which point it can be ejected and reloaded. While this is far faster than reloading a traditional powder-based pistol, artificers found a way to improve the design further, by mounting a revolving cylinder, which can be fitted with several shots, and simply rotated between firings.
  • One-handed Dex-based ranged weapon, inflicting medium piercing damage. Reload as a swift action up to 2 times (total 3 shots), then reload as a std action, once you've retrieved more cartridges (typically a swift action).
• Revolving Musket: similar to the revolving pistol, but with bigger cartridges and a much longer barrel.
  • Two-handed Dex-based ranged weapon, inflicting heavy piercing damage. Reload as a swift action up to 2 times (total 3 shots), then reload as a std action, once you've retrieved more cartridges (typically a swift action).

Consumables

Assault

• Black Powder Bomb: a simple metal container, stuffed with black powder, and fitted with a power cell. When the cell is activated, you have about 3 seconds before it transfers enough heat into the powder. Then it explodes in a burst 3 for heavy explosive damage. It's about as large as a softball and weighs about twice as much, so most people can chuck it a safe distance away in that time.
• Smoke Bomb: similar to an ordinary bomb, the smoke bomb has slow-burning powder, and a low-pressure container, so when it fires, it doesn't explode. Instead, it produces a thick cloud of opaque, choking smoke, filling a circle 3. Each round the smoke expands by 1 square. At circle 6, it provides only partial concealment. At circle 10, it disippates.

Control

• Net Launcher: Requires a special tool, which is a simple device to hold the canister. The canister does all the work. About the size of a large coffee can, the canister contains its own powder and power cell, triggered by the launcher. Once fired, the powder can launch its payload a reasonable distance (standard range), while also providing it just enough spin to spin itself open. The payload is a tightly-packed circular net of fine chains or wire ropes (ordinary ropes would burn) with weights on the outer circumference. Aimed well, it can fully enclose a medium creature, with the weights wrapping around a few times before (hopefully) hooking onto the chains/ropes with attached hooks, to fasten the net closed.
  • Std, ranged; roll Ranged vs Dex defense. On success, medium or smaller creature is netted. They can only move 1 square per move action, and must pass a Dex defense roll each time they do, or else fall prone. Escaping requires a standard action, rolling Strength against the burst DC of the net (TBD), or Escape Artist against the DC of the original attack.
  • At your option, you can fire containers that have a trailing chain or rope, which stays attached to the launcher. Thus, on a successful net, you now have a line attached to the target. Some artificers secure the launcher itself to a belt or harness so the victim's movement won't wrench it from their hands.

Powered Devices

These each require an energist of at least rank 1.

Assault

• Burning Fist: An elaborately-carved, dragon-stylized gauntlet, with a fire energist slot, several internal triggers, and output ports for belching flame. This one-handed gauntlet produces flame in various ways:
  • Dragon's Breath: Wrist-mounted, adjustable flamethrower. At-will, either cone 4, light fire damage, or line 4, medium fire damage. (Cone is a sweeping motion; always sprays in a line)
  • Finger of Flame: Single finger produces a terribly bright, hot flame, which can cut as well as an acetylene torch.
  • Fireball: Emitter in palm produces flame while closed fist contains it into a ball; ball can be thrown a ways before exploding, or can remain focused into a searing orb. Recharge 33%, ranged, burst 3, medium fire damage or single-target heavy fire damage.
• Freeze Ray: This one-handed weapon is constantly frosted over and quite cold to the touch. Fire modes:
  • Endothermic Blast: At-will, range 3; medium cold damage plus Chilled (50% movement reduction, Con ends). Against Chilled targets, causes Frozen instead (unable to take actions or move for 1 rd, Con negates, damage ends).
  • Icicle Lance: At-will, ranged; medium piercing cold damage, or heavy against chilled/frozen targets. Doesn't break Frozen.
  • Ice Wall: Recharge 25%, ranged, wall 1/level; creates a 20-ft high wall of ice that blocks line of sight and line of effect. Each 20-ft square section has HP equal to a max heavy damage roll. Lasts until end of next round.
• Lightning Gun: This heavy iron gauntlet features a pair of parallel rails, which can be used to jab (medium piercing damage), or can conduct electricity for various lighting attacks:
  • Tesla Coil: At-will, range 2, chain 2/2; medium lightning damage.
  • Lightning Bolt: Recharge 33%, line 10x1; medium lightning damage.
  • Shock Bayonet: Recharge 33%, melee; medium piercing damage plus medium lightning damage.
• Stun Baton: At-will, melee; target is stunned for 1 round (Con reduces to half movement and disadvantage to attacks). Lightning resistance/immunity applies.

To do:

• Dragon's Maw
• Cryo Cannon
• Lightning Rod

Defense

• Camouflage Cloak: Fitted with a water energist, this cloak can change its form and color readily. As a swift action, if you already using Stealth, you become effectively invisible until you move or attack. This doesn't make you invisible with an illusion, but rather forms a convincing extension of your surroundings to render you nearly impossible to detect visually.
  • Rank 2: use while moving slowly
  • Rank 3: doesn't break on attack (predator camo)
• Shield Module: This chest-mounted device takes an earth energist. While active, it produces a field of energy which grants all the benefits of heavy armor without all the bulk. Effectively, it produces an invisible barrier of pure inertia, which interferes with incoming attacks. At idle, it maxes out at given capacity, and each time it absorbs damage, it loses capacity, slowly regaining it if not further drained by more attacks.
  • While wearing, you gain Absorb 50%, limit 1 each round. The limit stacks until it reaches its maximum: 1/level + Int. Any damage you take is affected by this Absorb.
  • For example, a 5th-level artifcer with +3 Int has a maximum of 8. He's been wearing the module for hours, so it's at maximum. He is surprisingly attacked, suffering 10 damage from the arrow of an unseen attacker. The shield absorbs 50% of the damage; the artificer suffers 5 damage, and the shield's limit is reduced to 3.
  • Before he can react, another unseen attacker pushes him off a ledge; he falls, suffering 12 falling damage. The shield could normally absorb 6, but its current limit is 3, so it absorbs 3, and he suffers the remaining 9.
  • Next round, just before he plots his response to this heinous attack, the shield's limit regenerates from 0 to 1.
  • Ideas for higher ranks:
    • Hardness
    • Retribution
    • Store the damage, release it later
    • Wider shield to protect allies
    • Hand-mounted shield for blocking (separate tool, but same energist? hmm)

Enhancement

• Aimbot 1000: This set of lenses can be mounted to a headpiece, in order to provide assistance aiming projectiles. So mounted, it provides a +1 hit rating to ranged attacks and powers. Additionally, it can be fitted with power cells, which can imbue a brief sentience and motility to projectiles. As a swift action, costing 1 power cell, you imbue a ranged attack with the ability to guide itself toward a hit. This modifies your attack roll as such: a critical miss is still a miss, any hit is a critical hit, and any non-critical miss is a regular hit. For the purposes of total avoidance (i.e. Dodge/Parry), the attack is not eligible for such defenses. For setting the DC for any other effects, use the result of your roll as normal.

Mobility

• Jumper: This back-mounted device takes an air energist, and comes equipped with several flaps and winglets that can be fitted to the arms and legs. It has a primary outlet, in the shape of a narrowing tube that points downward and slightly backward. When triggered, it can produce a blast of air so powerful it can lift and propel the wearer. They can then use the flaps and winglets to slightly adjust their trajectory (although it's mostly about how they aimed the backpack when triggered), before inevitably landing with about the same amount of kinetic energy they were launched with. Fun, and very dangerous.
  • Recharge 33%, move; you jump up to 12 squares horizontally (height = 1/3 length), or up to 6 squares vertically. Thereafter, you suffer falling damage equal to 1d6 per square of height, plus additional falling damage if your landing square is lower than your starting square. You are allowed a Dex defense roll for half damage; if you fitted the winglets/etc, you suffer half damage on failure and no damage on success. If you land on an object or creature, you split the damage between yourself and the target.
• Hoverboard: This relatively simple vehicle, when equipped with an air energist, hovers a few inches above the earth. Naturally, it experiences very little friction in this configuration, so, if propelled forward, you can ride it at a satisfying speed. It requires proficiency in order to use properly, or else you must pass a Dex check each round (DC 10 + movement speed) or fall off. With proficiency, it grants a movement speed of Dex + proficiency, ignoring difficult terrain, and even works over water. If you are not in a position to propel yourself, you can spend a move action to coast along at half the previous round's speed (minimum 0). It does not cling to walls indefinitely, but during a move action, it can follow any surface up to 90 degrees (walls, not ceilings), as long as you end on a reasonably-stable surface. Thanks to straps on the board, you can also jump normally during a move, if you need to clear a chasm or void that the board would otherwise fall into.
  • With a rank 2 air energist, it can levitate up to 10 squares, and can cling to walls at rest. It can follow ceilings during a move.
  • If you mount a power cell to it, you can activate it as a swift action, causing it to grant bonus movement. When mounting, you choose the bonus speed, from 1 to 5. The power cell has 10 squares of movement in it, so at 5 squares, it is expended in 2 rounds, and at 1 square, it expends in 10 rounds. Once activated, the bonus movement becomes your minimum movement speed; if you do not move at least that much each round, you fall off the board and it keeps flying away. The power cell burns until expended--it cannot be canceled once activated.

Rank 2 (expert)

Tools

Weapons

• Shotgun
• Rocket launcher
• Sniper rifle

Other

• Universal Translator: Constant; this headgear combines an earpiece, a mouthpiece, and a lens, granting the ability to understand any non-archaic form of verbal or written language you perceive, and translating your own spoken language into the same via a croaking, mechanical voice. Grants advantage to Linguistics checks to interpret archaic or magical languages.

Consumable

Control

• Transmogrifier Ray: Power cell, ranged; target becomes a useless animal (Con ends, damage ends).

Powered Devices

Assault

• Etherlance: Aether energist powered, shoots a ghostly beam that can penetrate walls and armor, harms ethereal creatures.

Rank 3 (master)

Tools

Other

• Etherscope: Constant; you can see into the ethereal plane, granting the ability to see ethereal, incorporeal, and invisible creatures (though not necessarily the ability to interact with them). You can also see magical energy, detecting the spellcasting type and max level of all creatures in your line of sight.

Paths

Golem Crafter

Make golems, empower them with energists.

Armor Jockey

Animated armor protects you, has extra slots

Gunsmith

Ranger maneuvers? More a hybrid than an Artifice specialty.

Etherealist

Leaning into magic a bit, directly using elemental energy to do things without a device.

Other Ideas

• Reactor: a tool which you put multiple energists into, and it produces power for multiple devices (more than you otherwise could) using cabling, pipes, etc.
• Differential Reactor: a special reactor that harnesses the innate enmity between fire/water or earth/air energists, causing their antipathy to produce "orthagonal" power (aka fire/water produce earth or air, etc)

Balance

Trying to balance not by # of known schematics, but by something I can control via level.

Obviously, energists are a rare resource that the most powerful devices require. Power cells can be hand-waved as a daily consumable similar to Alchemy. Both can be looted from enemies or bought from suppliers, so that's something to think about.

Leaning into the fiction a bit more, what about this:

• Every Artificer has a Reactor of some sort (powered by an energist).
• The Reactor produces a resource called Steam, which is level-limited.
• All normal devices use Steam--pistols, hoverboards, universal translators, etc. It drives the clockwork needed to make things go.
• Some items use more Steam than others. It's possible to say that a rank 2 device requiring 2 steam is too complex to operate without Expert skill, even if you have plenty more than 2 Steam.
• Some items are so powerful they can't rely on steam alone: they need their own energists.

Limiting energists is tricky. One idea is that they have both constructive and destructive resonance. Two Earth energists overpower each other. A fire and water energist cancel each other out. Thus, you max out at 3 under normal circumstances: one fire/water, one earth/air, and one aether/nether.

But maybe there are more dimensions? Aether/Nether is the expert level, increasing total cap to 3, and adding new possibilities. Could there be another axis, or several more? Brainstorming:

• Feywild/Shadow/Infernal: doesn't seem inherently higher-level than Aether/Nether. Maybe a side option if you have an Invoker friend. Obvious drawbacks.
• Radiance/Darkness: similar to Aether/Nether, but not quite. Too subtle a distinction?
• Order/Chaos: kinda esoteric, but maybe neat.

Maybe the master-level ones aren't so straightforward, and come with their own drawbacks (and relatively few devices) unlike Aether/Nether.

Naturally, golems and armor jockey suits have their own reactors with their own, much higher Steam max.

Crystals

Where would Artifice be without crystals?

So it seems some natural crystals have interesting properties: they can act as a capacitor to certain elemental energies. They can be charged naturally in power nodes or ley lines, or by contact with elemental beings. They can also be grown and charged deliberately by Crystaliers, using tools of Artifice designed for the purpose.

Energists aren't crystals. They are continuous power sources--living nodes of elemental power, ever replenishing. Their energy can be captured in crystals, but such energy would be finite and expendable. Thus: power cells.

Crystals can be things other than capacitors. In total:

• Capacitors: store elemental energy
• Foci: given input of elemental energy X, output energy Y
• Engine: given input of elemental energy X, create quasi-magical effect Y

Foci are often used within larger constructions, as part of the "plumbing" that makes an advanced construct work. But they can also be used directly, such as in weapon form. Crystals that channel, say, fire energy, can be carved in such a way as to produce a narrow beam of flame when charged, or perhaps a wide spread. A combination capacitor-focus could perhaps build up a charge, then release it as a tightly-bound ball which can be launched before degrading seconds later into a huge explosion of flame.

And yes, these are the same crystals used by Jewelcrafters to give stat buffs.

Different Reactors

Why use Steam? Why not Aether or Nether? Or lightning, or fire?

This is interesting, but it sounds complicated. Steam powers mechanical motion. If you need a bunch of fire, you need a fire (or Aether) energist.

If you need to pipe a bunch of elemental or aether energy to multiple devices, that might be a separate thing from Steam (probably specific to Armor Jockey).

In fact, the rule of thumb might be this:

• Armor Jockey's physical capabilities are steam-based, such as:
  • Movement speed
  • Melee attacks
  • Advanced physical abilities, such as a dragon-shaped suit being able to fly
  • Guns, and any other steam-powered devices attached
• Quasi-magical abilities are limited by a reactor producing elemental energy, with multiple slots for output