Mechanist

The Mechanist is an artificer who has mastered the magical engineering of robotics and have created a mechanized chassis that they don and integrate weapons and armor to face nearly any challenges that might face them. They power their mechanized chassis (often called a "mech" by these artificers) by the use of some powerful energy source such as a prismatic core, dragoncrystal, soul cage, or some other force. This allows for continual use even under very stressful situations. They must balance their combat effectiveness with the excessive heat that is generated by using their mechanized chassis. Utilizing a powerful energy source is a double-edged sword as the more stress exerted on the powerful mech, the more heat is generated, eventually leading to a critical level that needs to be vented or the mechanist might be scalded by the extreme heat.

Mechs are considered Large, even if the mechanist is a small creature. They are highly adaptable, able to integrate all kinds of weapons or armor into their chassis, and during combat the artificer uses their mech as an extension of their own bodies. When not in combat, the mech can still be operated by or travel just behind the mechanist, but unable to act intelligently beyond following the mechanist at the same pace.

Tool Proficiency

3rd-level Mechanist 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.

Mechanist Spells

3rd-level Mechanist feature

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. Your Mechanized Chassis is not automatically a spellcasting focus but can be integrated with an Advanced Arcane Focus Infusion, allowing spells to be cast through the Mechanized Chassis.

Mechanist Spells

Artificer Level	Spell
3rd	alarm, shield
5th	Arcane Lock, Enlarge/Reduce
9th	Glyph of Warding, Protection from Energy
13th	fabricate, fire shield
17th	Animate Objects, mass cure wounds

Integrated Arms

3rd-level Mechanist feature

Your mechanized combat training and your experiments with magically integrating weapons into your mech's chassis have paid off in two ways:

• You gain proficiency with martial weapons when they are integrated into your mech
• Once integrated, when you attack with a magic weapon through your mech, you can use your Intelligence modifier, instead of Strength or Dexterity modifier, for the attack and damage rolls.

Mechanized Chassis

3rd-level Mechanist feature

Your magical engineering has led to the creation of your Mechanized Chassis (or "Mech"). It is a mobile suit of armor and weapons that lacks intelligence, but can follow simple commands from you such as "follow" or "stay". See this creature’s game statistics in the Mechanized Chassis stat block, which uses your proficiency bonus (PB) in several places. You determine the creature’s appearance and design; your choice has no effect on its game statistics.

In combat, the Mech shares your initiative count, and you can don or doff it as a bonus action. Once donned, it's actions become your own, allowing you to use it's integrated weapons or armor as your action. In combat, the Mechanized Chassis and you become one and it's actions take over your own.
You can use it's integrated weapons or armor (that you integrated previously) to attack or boost your AC and provide half-cover for all those behind or near it.That action can be one in its stat block or some other action. If you are incapacitated, the Mech cannot take any action beyond Dodge.

Once you use it's integrated weapons or armor and an action or take a strength or dexterity saving throw, or use a reaction, you gain one level of Heat. You have a Heat cap equal to 2 + your proficiency bonus. Once you reach your Heat cap, you take 1d10 fire damage every round until you vent the heat as an action. Venting Heat at your Heat Cap as an action will expel the growing flames around you in a 5 foot square, dealing 1d10 fire damage to all creatures within that square. Otherwise, venting returns your Heat level to 0.

If the mending spell is cast on it, it regains 2d6 hit points. If it has been destroyed within the last hour, you can use your smith’s tools over a short rest to rebuild it, provided you are within 5 feet of it's component parts and you expend a spell slot of 1st level or higher. The Mechanized Chassis returns to functionality after with all its hit points restored.

Heat Cap

3rd-level Mechanist Feature

When you take an action, saving throw, or reaction through your Mechanized Chassis, you gain 1 Heat. Your Heat Cap equals 2 + your Proficiency Bonus.

Extra Attack

5th-level Mechanist feature

You can attack twice, rather than once, whenever you take the Attack action on your turn. This persists to your Mechanized Chassis.

Advanced Chassis System

9th-level Mechanist feature

You've created new ways to channel the heat or energy produced by your Mechanized Chassis to harm or protect. Choose either:

• When you hit a target with an Integrated Weapon attack, you can channel your Heat as magical energy through the strike to deal an extra 2d6 fire damage.
• When you use your Integrated Armor action, you can give 2d6 temporary hit points to all allies within 15 feet of you.

You can use this energy a number of times equal to your proficiency bonus, but you can do so no more than once on a turn. You regain all expended uses when you finish a long rest.

Overclocked Chassis

15th-level Mechanist feature

You have Overclocked your Advanced Chassis System and Integrated Weapons making them more powerful:

• The extra damage and the temporary hit points of your Advanced Chassis System both increase to 4d6.
• Your Mechanized Chassis gains a +2 bonus to Armor Class.
• Whenever your Mechanized Chassis uses its Deflect Reaction, the attacker takes force damage equal to 1d8 + your Intelligence modifier.
• Vent Heat can be used as a Bonus Action.
• You can use two different types of Integrated Weapons when you take the Attack action without switching.