Tools of the Trade

By the time you adopt this specialty at 3rd level, you're deeply familiar with employing its tools.

Proficiencies. You gain proficiency with leatherworker's tools and smith's tools, assuming you don't already have them. You also gain leatherworker's tools and smith's tools for free—the result of tinkering you've done as you've prepared for this specialization.

Crafting. If you craft a magic item in the armor or weapon category, it takes you a quarter of the normal time, and it costs you half as much of the usual gold.

Steam Knight Spells

Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Steam Knight Spells table. These spells count as artificer spells for you, but they don't count against the number of artificer spells you prepare.

Steam Armor

By 3rd level, you have developed advanced smithing techniques, combining them with your knowledge of the arcane arts, creating a suit of steam powered armor.

During a long rest, you may turn a suit of armor into Steam Armor. Whenever you roll initiative while wearing this armor, it instantly activates defensive wards to cushion incoming blows, granting you a number of temporary hit points equal to your Artificer level + your Intelligence modifier.

Finally, as a bonus action, you can overcharge your armor 3 times per day, gaining one of the following magical benefits:

• Pressure Capsule. Your armor closes tightly arround you, creating a vacum in which you have enough air to sustain yourself for the next 10 minutes.
• Self Repair. The armor deploys a cooling liquid that dresses your injuries. You regain a number of hit points equal to 2d4 + your Intelligence modifier.
• Power Surge. The armor injects you with a shot of pure adrenaline. For the next minute your speed is increased by 10 feet, and you may add your Intelligence modifier as a bonus on all Strength (Athletics) checks.

Only you may benefit from the features of your armor. The first armor you create is considered to have been paid for as a culmination of your research. Should you wish to make another Steam Armor, it's cost in materials is equal to twice the cost of the base armor you wish to implement it into.

Arcanomechanical Training

When you reach 3rd level, your combat training and your experiments with magic and have paid off in three ways:

• You gain proficiency with martial weapons and heavy armor.
• You may use your Intelligence modifier instead of your Dexterity modifier while calculating your Armor Class.
• You may use your Steam Armor as a spellcating focus for your Artificer spells, ignoring any somatic components for all spells with a range of self.

Advanced Offensive Protocols

By 6th level, you have integrated a series of cutting edge targeting technologies into the framework of your armor.

While wearing your Steam armor, you may reroll any 1 you roll on a weapon attack or damage roll, but must use the new result. Furthermore, once per turn when you roll the highest number on a melee weapon damage die, you may roll the die again and add it to the damage total.

Defense Matrix

At 14th level, you have mastered the required technologies to make your armor absorb impacts while storing some of the kinetic energy behind them.

While wearing your Steam Armor, all damage you take bar psychic is automatically reduced by an amount equal to your Intelligence modifier.

Additionally, whenever you suffer damage that isn't psychic or the direct result of a critical hit, you may use your reaction to gain advantage on all saving throws and opposed ability checks against effects that would reduce your movement speed, push you or knock you prone against your will. These benefits last until the start of your next turn. You may use this feature a number of times equal to your Intelligence modifier, requiring a long rest before you can use it again.

Art credit goes to rilleriller: https://https://thpix.com/media/432908582914992244