The mechanist focuses on creating a set of armor that they enhance as they expand their skill level.

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

Arcane Armor

Also at 3rd level, you craft a suit of armor that only you can use. You gain proficiency in Arcane Armor as well as gain a set of the armor. Only you can use the armor, and, while wearing it, your unarmed strikes deal 1d6 bludgeoning damage, you are considered proficient with this attack.

When you create the armor, you must choose a chassis. You can choose either Elementalist, Scout, or Unit and gain the corresponding feature.

Elementalist. While wearing the armor, your AC is equal to 15 + your Dexterity modifier (to a maximum of 2), you learn the Fire Bolt, Acid Splash and Shocking Grasp cantrips, they count as artificer cantrips for you. You also gain resistance to one of the following damage types (you choose): Acid, Cold, Fire or Lightning. You can choose an additional resistance at 6th and 14th level, you cannot choose the same resistance that you chose previously.

Scout. While wearing the armor, your AC is equal to 12 + your Dexterity modifier, you can use a bonus action on your turn to take the dash or disengage action.

Unit. While wearing the armor, you AC is equal to 18 and you have disadvantage on Stealth checks. If you move at least 20 feet straight towards a target while wearing the armor and then hit it with a melee weapon attack on the same turn, the target takes an extra 1d8 damage of the weapon's type. While wearing the armor, your size increases by one category up to a maximum of Medium.

You can create a new set of armor by spending 1 day and 250 gp worth of appropriate materials (as determined by the DM), when you do so, you may choose a different chassis. You can only have one set of arcane armor at a time.