Thaumaturgist

Thaumaturgists are a group of secretive Artificers whom feel that the greatest skill of an Artificer is to mold and shape metal into artificial life, as evidenced by their Metallurgy Workshops, mobile forges on legs made of Validium, a rare living metal. These constructs can serve a variety of functions, both in and out of combat. They're often very protective over their inventions and guard the secret of their craft carefully, rarely taking on apprentices. They guard their sources of Validium jealously, using their constructs as miners and guards and often barter with good dragons, offering protection and trinkets from far away for permission to mine Validium near them or their lair. The way their constructs are treated varies from Thaumaturgist to Thaumaturgist, with some seeing them like servants or slaves, built to carry out orders. Other Artificers give them sentience and names and treat them like a good friend or companion, a being that understands them and is willing to put up with their possible eccentricities.

Tool Proficiency

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

Mobile Metallurgy

Beginning at the 3rd Level, Thaumaturgist Artificers gain access to a Mobile Workshop as part of their initial equipment. It's similar to a Bag of Holding. While the player character is inside the workshop, they can spend 1 action to fabricate 1 construct out of Validium (Magically-enhanced living metal used only by Thaumatagist Artificers, treat it as adamantine for properties/appearance.). You are able to create and control an amount of constructs in total equal to half of your Artificer Level rounded up.

Validium costs 5 gold per pound and must either be mined or fabricated. Discuss with your DM how you obtain it, is it a plot point you need to work towards? Do you buy it from another trader, do you locate, mine and refine the ore yourself? Additionally, you can spend a spell slot or an amount of spell slots to transmute an amount of metal into Validium, altering the base metals properties and charging it with your own magical energy to give it the necessary properties. The equation for Validium Transmutation is 1 lb of metal + 1 1st Level Spell Slot = 1 lb of Validium. For example, 5 pounds of metal and a 5th Level Spell Slot or a 4th Level Spell Slot + a 1st Level Spell Slot would make 5 pounds of Validium.

The Mobile Workshop can hold up to 5 constructs at a time and cannot be used to store other things like a Bag of Holding, since when it collapses, it ejects material that doesn’t contain Validium inside it due to its properties.

While you are in the workshop during combat, the workshop takes up your token space on the map as if you were there. It always shares a movement speed, modifiers and HP total with you. You can still be targeted by spells and attacks as normal, and you take damage equal to the amount of damage the workshop takes while inside it. It is a free action to enter or leave the workshop or to send your constructs out or to bring them in for repairs/upgrades. If you are not in the workshop, it powers down and folds up.

You can equip your Artificer Infusions to your constructs instead of yourself. If that construct is destroyed, you regain the infusion but must find new materials to make another infusion.

When you Fabricate a construct, select one type, chosen from the options below:

Observation Drone
Tiny construct, unaligned
Armor Class: 10 + your Int Modifier.
Hit Points: 6 (1d6 + 3) + 3 times your Artificer level
Speed: Fly 30 ft.
Validium Weight: 3 Pounds
STR       DEX       CON      INT     WIS     CHA
2 (-5) 18 (+4) 12 (+1) 3 (–4) 16 (+3) 7 (–2)
Damage Immunities: poison
Condition Immunities: charmed, poisoned
Senses: Darkvision 60ft, passive Perception 13
Languages — (understands whatever languages you speak)
Actions
Claw. Melee Weapon Attack: Your Spell Attack Modifier to hit, reach 5 ft., one target. Hit: 1d4+4  slashing damage.

Sensory Link. You can connect your senses to the construct's as an action. you can see through the construct’s eyes and hear what it hears until you dismiss this effect as a bonus action, gaining the benefits of any Special Senses that the construct has. During this time, you are deaf and blind with regard to your own Senses.

Combat Automaton
Medium construct, unaligned
Armor Class 15
Hit Points 15 (3d6 + 3) + 3 times your Artificer level
Speed 30 ft.
Validium Weight: 5 Pounds
STR       DEX       CON      INT     WIS       CHA
14 (+2) 14 (+2) 14 (+2) 3 (–4) 10 (+0) 7 (–2)
Damage Immunities: poison
Condition Immunities: charmed, poisoned
Senses: passive Perception 10
Languages — (understands whatever languages you speak)
Actions
Multiattack. The Automaton makes a number of attacks equal to your Proficiency Bonus (rounded down).
Claw. Melee Weapon Attack: Your Spell Attack Modifier to hit, reach 5 ft., one target. Hit: 2d6 + your Intelligence Modifier
slashing damage.
Chain Cannonball. Ranged Weapon Attack: Your Spell Attack Modifier to hit, reach 30 ft., one target. Hit: 2d4 + your Intelligence Modifier bludgeoning damage.

Installed Weapon. Choose 1 melee or ranged Martial weapon. This construct is treated has having that weapon installed into its body. It cannot be disarmed or drop the weapon, but it can retract it to an inactive state. 

Servitor Construct
Small construct, unaligned
Armor Class 12
Hit Points 15 (2d6 + 3) + 3 times your Artificer level
Speed 30 ft.
Validium Cost: 2 Pounds
STR       DEX       CON      INT     WIS       CHA
10 (+0) 14 (+2) 10 (+0) 3 (–4) 12 (+1) 7 (–2)
Damage Immunities: poison
Condition Immunities: charmed, poisoned
Senses: passive Perception 11
Languages — (understands whatever languages you speak)
Actions
Claw. Melee Weapon Attack: Your Spell Attack Modifier to hit, reach 5 ft., one target. Hit: 1d6+2
slashing damage.

Tools. Select 3 Tools. The construct can make checks using those tools and is considered having and being proficient with the selected tools. It uses your Proficiency bonus for any checks. Additionally, you can expend your reaction to give your construct advantage on the check.

Validium Magitech

By 3rd level, your tinkering and crafting has born the fruit of small mechanical constructs by combining mechanics with magic and the properties of Validium. They are friendly to you and your companions and obey your commands. When gaining this feature, it allows you to create 1 construct per turn from the list of constructs in the Thaumaturgist Subclass using your action and bonus action in combat, if you have less than your maximum amount of constructs allowed by Mobile Metallurgy. You may spend time during short rests to build a new construct. The total number of constructs you can control in total that are created with this feature is equal to half of your proficiency modifier (rounded down). The constructs can collapse down to be one size category smaller for easier transport. Activating them requires an action after which they may act immediately. You can activate multiple constructs at once with one action, but if you do, your movement speed is reduced to 0. If by using this ability and Mobile Metallurgy you have more constructs than your maximum by the end of combat, reduce the HP of constructs of your choice to 0 until the maximum is reached.

In combat, a construct shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, or follow orders you give it. Ordering just 1 construct costs a free action, but to direct 2 or more of your active constructs requires an action.

If the Mending spell is cast on a construct, it regains 2d6 hit points. If it has been destroyed within the last hour, you can use your tinker’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 construct returns to life after 1 minute with half of it's hit points restored, but it has disadvantage on all attack rolls and ability checks until you next take a short or long rest.

Tempered Validium

At 5th level, you have figured how to craft better constructs. Any Construct you create gains an additional bonus to its Armor Class and any ability rolls they do equal to half of your proficiency bonus, rounded down. Whenever a target is struck by an attack or spell from one of your constructs, add your Intelligence modifier to the damage roll. This effect can only trigger once per round. You can cast your spells through the constructs you make out of Validium through your class abilities and you can use them as an Arcane Focus, although you must be within 30ft of the targeted construct to use this ability.

Your constructs can make one additional attack if they take the Attack Action, unless they have Multiattack.

At the start of your construct's turn, if they are below their maximum HP by at least 15 hitpoints, roll 1d4. Your construct heals that amount of damage as you've learned how to preserve a fragment of the self-regenerative properties of Validium. If your construct's HP is reduced to 0, it does not regenerate and must be repaired by you, either through the Mending Cantrip or making a Tinker’s Tools check.

Additionally, when constructing a construct, you can reduce the Validium Cost by paying in blood, 5 gold pieces worth of it as equivalent exchange. Take 2d8 + your Constitution Modifier slashing damage for each pound of Validium you wish to substitute as you use your ferrous blood as a magical and material substitute for the Validium, transmuting it. This damage cannot be reduced by any means. You can only perform this substitution once per short or long rest as doing so physically and magically exhausts you.

You gain additional servitors through this ability at this Level.

Artillery Automaton
Medium construct
Armor Class: 14
Hit Points: 20 + 2 times your Artificer Level.
Speed: 30 ft.
Validium Cost: 5 Pounds
STR DEX CON INT WIS CHA
10 (+0) 16 (+3) 18 (+4) 14 (+2) 11 (+0) 5 (−3)
Damage Resistances: poison
Condition Immunities: charmed, exhaustion, frightened, incapacitated, paralyzed, petrified, poisoned
Senses: darkvision 60 ft., passive Perception 10
Languages: understands the languages you speak
Challenge: —
Proficiency Bonus: equals your bonus
Actions
Multiattack: The construct makes a number of attacks equal to your Proficiency Modifier.
Light Accelerator: Your spell attack modifier to hit, reach 60 ft., one target. Hit: 1d8 + your Intelligence Modifier Radiant Damage.
Kinetic Kill Vehicle: Your spell attack modifier to hit, reach 90 ft, one target. Hit: 1d6 + your Intelligence Modifier Bludgeoning Damage.

Empowered Magitech Matrix

Arcana Automaton
Tiny Construct
Armor Class: 15
Hit Points: 5 + 3 times your Artificer Level.
Speed: 20 ft, 30 ft flying
Validium Cost: 1 Pound
STR DEX CON INT WIS CHA
6 (-2) 12 (+2) 18 (+4) 20 (+5) 5 (-3) 5 (−3)
Damage Resistances: poison
Condition Immunities: charmed, exhaustion, frightened, incapacitated, paralyzed, petrified, poisoned
Senses: darkvision 60 ft., passive Perception 10
Languages: understands the languages you speak
Challenge: —
Proficiency Bonus: equals your bonus
Actions:

Cast Spell: Your Arcana Automaton knows the following spells: Ice Knife, Firebolt, Detect Magic, Healing Word, Hex, Hellish Rebuke, Augury. It shares your Spell Attack Modifier and Spell Save DC and Intelligence is the casting modifier. As an action, it can cast one of the listed spells. It cannot cast a listed spell of a higher level than you are able to cast.
Reactions:

Disrupt Arcana: Your Arcana Automaton can invert its magical field and produce an anti-magic shockwave to disrupt magic around it, although this has a damaging effect on itself. The automaton is built with 3 charges of this ability. It can use your own or its reaction to expend 1 charge and have your Arcana Automaton cast Counterspell, it takes 2d4 radiant damage from doing this and the damage cannot be reduced by any means. If all charges are used, the Automaton falls apart and immediately drops to 0 hitpoints as the antimagic destroys the spells cast on it and disrupts Validium's magical properties that animate it. The automaton cannot regain charges through any form of rest and you must spend 10 minutes to completely deconstruct the automaton and remove the antimagic properties before spending another 10 minutes to reconstruct it with all charges restored by spending a 1st Level or Higher Spell Slot and using your Tinker's Tools.

Archmagical Engineer

Starting at 15th level, you've reached the pinnacle of your crafting abilities. You gain a bonus to your initiative equal to your Intelligence Modifier. The number of constructs you can have crafted with Mobile Metallurgy increases by your Proficiency Bonus. Additionally, all your constructs receive the following benefits:

• Resistance to 1 damage type of your choice, chosen when crafting the constructs. This choice can be changed as a free action if you recall a construct to your workshop, but you can only change this choice once before having to deconstruct it and make a new construct with the chosen resistance.
• In addition, you know at all times in what direction and how far your constructs are from you, provided they are on the same plane of existence.
• If your constructs make an attack using their action, they can use their bonus action to perform an additional attack or cast a cantrip as a bonus action if you cast a spell through it as an action.
• Roll 2d4 + your Intelligence Modifier during the start of each of their turns to heal the rolled amount if they are missing at least 15 hitpoints from their hitpoint maximum as you fully preserve Validium's auto-regenerative abilities.
• If you cast a Levelled Spell as an action, you can use your Bonus Action to command 2 constructs within 90ft of you at the cost of half of your movement.