Dreadnaught

Clad head to toe in plates of steel, the dreadnaught
stands a veritable mountain of impenetrable
defense. When the dreadnaught charges onto the
battlefield, the earth trembles beneath their
armored feet. Faced with the inability to harm
such a foe, their enemies often break and run in
fear. The dreadnaught cannot be stopped, cannot
be resisted, and they shrug off all but the most
powerful of blows.

Mountain of Steel

At 3rd level, while wearing heavy armor you reduce the damage you suffer from slashing, piercing, and bludgeoning damage from nonmagical weapons by an amount equal to your Constitution bonus. Additionally, you automatically begin with one success whenever you must start making death saves.

Fear of Failure

At 7th level, if an attack fails to damage you, you may use your reaction to make a Strength (Intimidate) skill check against a DC of 8 + your opponent’s proficiency bonus + opponent’s Wisdom modifier. If you are successful, that opponent suffers disadvantage on all attacks made against you until the end of their next turn.

Impenetrable Defenses

At 10th level, you treat all critical hits as normal hits while wearing heavy armor.

Improved Impenetrable Defenses

At 15th level, magical weapons no longer bypass your damage resistances. In addition, you add your Constitution bonus to all death saves.

Unyielding

At 18th level, when you suffer enough damage to be reduced to 0 hit points, you may spend a reaction to be reduced to 1 hit point instead a number of times equal to your proficiency bonus. You get all uses back on a long rest.