Path of the Malfunctioning Machine

This machine is an ancient construct that is slowly deteriorating causing some fun effects.

Iron Heart

When you choose this subclass at 3rd level, you gain proficiency in heavy armor. Additionally, rage and other class feature function normally while you wear heavy armor.

While raging you may add an additional d6 of damage due to the weight behind the strikes.

Self Repairs

At 3rd level, you gain proficiency with Smith’s Tools and resistance to Fire.

Additionally you may use your action to heal 1d8 plus your CON. You may use this a number of times up to your Proficiency.

Mythril Upgrades

Add your level in extra health (this scales with level). 

Additionally when an adjacent ally is attacked you may use your reaction to swap places with them and take the attack. If this attack hits you may attack once in retaliation.

Malfunctioning Mechanisms

Your old age systems are starting to deteriorate causing the occasional spark but more importantly it has rotted out your safety functions allowing you to go past what is safe.

Before any attack while raging you have the option to take 1d6 or 1d12 damage (no resistances will stop this damage) and add 2x the roll to your damage if you hit.

Additionally you may use a bonus action to attack with your weapon and deal 1d8 to yourself.