The inventor always seems to have a gadget up his sleeve. And on his wrist. And on his belt. And, is there one on his sword? Probably! 

When an artificer falls down the slippery slope of creation, nothing will quench his thirst to make. He will constantly thirst for the feeling of achievement, and will never run out of things to do. An artificer who goes down this path will eventually find that conventional magic has eluded him. Everything now takes the shape of an invention. To aid in his work, the Inventor will build a suit or mech. This grants him new abilities as he continuously tinkers with it.

Tool Proficiency

3rd-level Battle Smith feature

You gain proficiency with smith’s tools. If you already have this proficiency, you gain proficiency with one other type of artisan’s tools of your choice.

Gadgets

3rd-level Inventor feature

With your extreme focus on creation and invention, you have forgotten conventional spellcasting as described earlier in the Artificer class. Aware of magic, but not how to cast it, in order to learn a spell you must invent a gadget to use it! Be creative with it. The gadget can be wearable, wieldable, or attached to something else. 

This feature adds access to every spell in D&D. You may not create a gadget if you cannot logically explain how such a device would work. You are limited to natural abilities, sensing, detecting, anything that can be represented by a firearm, etc.

For Example,

In order to learn the Fire Bolt Cantrip, you might invent a boot with a bucket of woodchips on the toe. To cast it, you light the woodchips and kick! While the storyline of this gadget requires woodchips, the Fire Bolt Cantrip does not consume any materials. So this gadget does not require any materials to use.

For every gadget created, an engineering drawing (of any level) must be presented to the DM for approval.

Gadgets are subject to the same limitations as Artificer Spells. When used by another player or character, the gadget requires attunement and will use their own spell slot.  The artificer is always attuned to his own gadgets. These gadgets count as the spellcasting focus that casting requires. If the gadget is lost or broken, a new one must be made before the spell can be used again. No matter how the gadget works in the story, its material consumption will not change from the base spell. Using a gadget will consume the corresponding spell slot for the spell it represents.

The maximum number of gadgets (for first level spells and up) any being can wield is equal to their intelligence modifier + half of their artificer level, rounded down (minimum of one gadget). If the character attempts to wield more than this number of gadgets at once, they will clumsily drop and irreparably break a random number of them. The creation of a gadget requires one hour. They can be discarded or destroyed at any time.

Gadgets that represent cantrips require a level of attunement that is unachievable for any character other than the Inventor that created it.

Intelligent Strike

3rd-level Inventor feature

Your extensive engineering study and experiments with magic have paid off in a big way. When you attack with a magic weapon, you can use your Intelligence modifier, instead of Strength or Dexterity modifier, for the attack and damage rolls.

Materials I

3rd-level Inventor feature'

Growing accustomed to craftsmanship, you can now use wooden building materials. 

Material	Durability	Crafting Time
Twigs / Vines	1d4 uses	5 mins - 3 hours
Solid Wood / Bone	2d4 + PB uses	30 mins - 8 hours
Hard Wood	2d4 + 2 × PB uses	1 hour - 8 hours

Suit Up

3rd-level Inventor feature

Your tinkering with plentiful gadgets has borne you a mechanized suit; an apparatus made of twigs. Powered by your inherit artificer magic, it obeys only you. You determine everything about its appearance - whether it has two legs or four, etc; your choice has no effect on its game statistics. Every configuration requires an engineering drawing (of any level) to be approved by the DM before it can be made. Your suit is a magical item with many properties that set it apart from standard armor. It grants the wearer new abilities depending on its configuration, in addition to enhancing combat prowess.

Your suit can operate as armor or a separate mechanical creature. See its stat block below. Removing or Donning the suit requires a full turn (action, bonus action, and reaction). When used as armor, the player can use any of the suit's actions as their action.

In combat, if the suit is acting as a separate mechanical creature, it shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take another action. That action can be one in its stat block or some other action. If you are incapacitated, the suit can take any action of its choice, not just Dodge.

In combat, if the suit is acting as a suit, it has no autonomy - it merely buffs the Inventor's abilities. Enemies cannot aim an attack at the player while the suit is on. All attacks and damage are performed on the suit. The suit attaches to you and can't be removed against your will. No matter the material of the suit, Heat Metal will have no impact on the Inventor inside.

If the mending spell is cast on it, the suit regains 2d6 hit points. If it has died within the last hour, you can use your smith's tools as an action to revive it, provided you are within 5 feet of it and you expend a spell slot of 1st level or higher. The suit returns to life after 1 minute of tinkering, with all its hit points restored. If the suit loses all its hit points while acting as armor, it falls off of its wearer, leaving them exposed.

You can choose what material to make your suit out of. See the Materials I feature to find a description of each. Every material will have its own properties and specialties. Changing the material of your suit can be done over the course of a long rest, within reasonable limits. You can't change it to a type of wood if you are on a barren desert island. Choose a material to start with and you will see the corresponding suit's stat block:

1. Twig Suit

This suit is light and nimble, but did it just creak?

 

2. Solid Wood Suit

The suit feels much sturdier, in the worst ways. But if it's sturdy now, it'll probably be sturdy while being hit.

 

3. Hard Wood Suit

This is somehow less comfy than the Twig suit but it hurt to make so it should hurt to hit!

 

4. Stone Suit

Stone is hard to craft with, and this was no exception. But when you need strength in a hurry, it's not a bad way to go!

 

5. Copper Suit

A suit made of copper.

 

6. Brass Suit

A suit made of brass.

 

7. Bronze Suit

A suit made of copper.

 

8. Iron Suit

A suit made of Iron.

 

9. Aluminum Suit

A suit made of Aluminum.

 

9.1 Lead Suit

A suit made of lead.

 

9.2 Nanoconstruct Suit

A suit made of Nanoconstructs.

<Honestly, TBD>

 

Upgrades - Mimic

3rd-level Inventor feature

Starting at level three, you can begin crafting upgrades to your suit. These upgrades can attempt to mimic any simple ability. There are multiple steps involved in upgrading your suit. They will be outlined as follows:

1. Choose a desired ability.
2. Make a realistic plan to implement this ability to the suit.
3. Choose a material for the upgrade.
4. Upgrade!
5. Test.

Choose a desired ability

First, you must have an idea of what you want the suit to be able to do. At this level, you are limited to characteristics and abilities that you know of in natural wildlife.

Make a realistic plan to implement this ability

Next, you must come up with a plan in the form of a proposal. Think about what the upgrade will actually be. If you want to add spikes to your arm, you may create a plan to tie thorny vines around it. This is what you will share with your DM when you start the upgrade process. At this point the DM cannot say whether or not the upgrade will work.

Choose the material for the upgrade

This is a crucial step for a few reasons. It determines how long the upgrade will take, how long the upgrade will last, and how the upgrade will function. If a material doesn't make sense for its proposed purpose, the DM may make it fail. As you level up, you will gain access to more and more materials. These materials can be used for small upgrades, or upgrading the entire suit. See the Materials I section for the materials you have available to you. 

Crafting time can be interrupted and restarted without penalty for longer upgrades.

Upgrade

Once all those details are ironed out, perform the upgrade! Depending on the plan and material, your DM may request that the upgrade takes a longer amount of time.

Test

Just like any Inventor, you must now test the upgrade. Every use of the upgrade will consume one of its durability points. When it runs out of durability points, it breaks irreparably. You can remake the upgrade, but this will take new materials and another length of time. The DM holds sole power over whether or not an upgrade will perform as intended, and you will not know the outcome unless you attempt to test the upgrades. If you choose a bad material for a certain ability, you may find that it does not go as planned!

The DM can also factor experience into his decision on effectivity. Maybe the first time you attempt a difficult upgrade fails, but the second time is more likely to succeed. Upon a failed test, the DM must make clear whether or not the idea will work with more practice. This is something an Inventor could feel even in failure. Some things are worth a second try, and some are not.

For example,

the Tabaxi claws allow them to climb with a high speed, and deal slashing damage instead of bludgeoning damage. Your character can attempt to add claws to his suit, using twigs for faster prototyping.

Your plan may be to add 3 triangle spikes to the end of your arms and legs. You and your DM agree that crafting time for these claws would be roughly 10 minutes. You rolled a d4 dice and got a 2. That means these claws can be used 2 times before they break. Both climbing counts as a use, and attacking with them counts as a use. For an action like climbing, don't track a separate use for every movement. Just count it used once the climb is attempted.

To test these claws, you go to a solid metal wall. On an attempt to climb it, you use 1 durability point and the DM informs you that it does not work. The wood cannot pierce nor find grip on the solid metal wall. He also informs you that wood would likely never do the job here.

You determine an easier test might be a wall made of dirt. On an attempt to climb, you use another durability point. This time, the DM informs you the climb is successful. The twigs easily made it through the packed soil.

Perhaps to climb that metal wall you need metal claws of your own?

Materials II

4th-level Inventor feature'

Growing accustomed to craftsmanship, you can now use stone and soft metal building materials. 

Material	Durability	Crafting Time
Stone	3d4 + PB uses	4 hours - 8 hours
Copper	3d4 + 2 × PB uses	2 hours - 8 hours
Brass (Copper, Zinc)	4d4 + PB uses	4 hours - 8 hours

Autonomy Level II

5th-level Inventor feature

With the bond between Inventor and Invention growing, you have reached a new level of attunement with your suit. Now, whether or not the suit is being worn, it will take a full turn immediately after yours. It is also no longer limited to Dodge, but can now Attack or perform any other task a player can.

Its full turn includes movement, action, bonus action, and reaction.

You may choose to take an extra Attack on your turn, but the focus that requires will momentarily sever your connection with your suit. It will skip its upcoming turn.

Materials III

6th-level Inventor feature'

Growing accustomed to craftsmanship, you can now use hard metal building materials. 

Material	Durability	Crafting Time
Bronze (Copper, Tin, Other)	4d6 + PB uses	1 hour - 8 hours (Easier to cast)
Iron	6d6 uses	4 hours - 8 hours

Materials IV

8th-level Inventor feature'

Growing accustomed to craftsmanship, you can now use advanced metal building materials. 

Material	Durability	Crafting Time
Aluminum	6d6 uses	4 hours - 8 hours
Lead	50 uses	8 hours - 24 hours

Advanced Mechanisms

9th-level Inventor feature'

At this point you know and understand most basic mechanism like the back of your hand. Constantly striving to improve your skills, you have realized new ways that your suit can be upgraded, beyond what you've already done. Whether it's adding springs to the joints, hydraulics, or extra armor, you can now craft upgrades that change the suit's stats. No stat can be upgraded more than two effective points*.

For every stat upgrade in action, your suit requires exponentially more maintenance. This maintenance comes at the expense of one spell slot per upgrade per day. The spell slot level must be of a level equal to the impact of the upgrade. You may choose to stack upgrades onto a higher level spell slot. For example, a lvl 1 upgrade and a lvl 2 upgrade can be maintained by a single lvl 3 spell slot.

For Example,

If you add advanced armor mechanisms, you may decide increase your suit's AC by 2. This will effectively take away one of your 2nd level spell slots until you decide to deactivate the upgrade. After every long rest you must check off a spell slot for every active Advanced Mechanism.

*Effective points means the actual felt impact of the upgrade. Raising AC by +2 has a direct impact on gameplay. But raising Strength by +2 only increases the modifier by +1. That is 1 effective point.

Materials V - Nanoconstructs

15th-level Inventor feature'

Your crafting prowess is now nearly unmatched in all the land. Not only that, but the artificer magic flowing through your veins is on another level. You have not only discovered how incredibly small objects can be, but your power is enough to control millions of them as tiny, nearly invisible constructs. Anything made out of nanoconstructs is nearly indestructible, since any time they take damage they can self-repair.

Material	Durability	Crafting Time
Nanoconstructs	Yes	24 hours*

* Making the nanoconstructs themselves takes a lot of time. Once a pool of nanoconstructs has been made, you can change the nature of any nanoconstruct upgrade in a manner of seconds. For example, nanoconstruct Tabaxi claws can be transformed into arm spikes in the timespan of one action.

Sensing Devices

15th-level Inventor feature'

With the advancements you have been able to produce in technology, you have found a way to easily create sensing mechanisms that no longer need magic to power them. From this point on, any gadget that is used to sense or observe any aspect of the world can be used without expending a spell slot.

Transformer

18th-level Inventor feature

Your understanding of the universe and its materials now goes down to the atomic level. With incredible focus you can even feel the orbit of electrons and count the number of protons in any given atom. With this newfound knowledge, you can channel all your artificer might to transform 1 cubic meter of material into any material of your choice. This takes a lot of power. It will consume:

• 4 first-level spell slots
• 3 second-level spell slots
• 3 third-level spell slots
• 3 fourth-level spell slots
• 1 fifth-level spell slot

Autonomy III

20th-level Inventor feature

At this point, if you can think of a machine, you can build it, and you can build it fast. There is now no limit to the number of constructs you can create, and there is no limit to what those constructs can do. Again, a clear plan must be presented to the DM before a machine can be built, but with their approval there are literally no limits on what is possible.