Path of Colossus

Some Barbarians do not beseech spirits or borrow the strength of giants — they become something greater. Those who walk the Path of the Colossus unleash a violent metamorphosis buried deep within their flesh. When their rage ignites, muscle and bone are engulfed in living metal, skin hardening into gleaming steel with a sound like a forge roaring to life. Their footsteps toll like war drums on iron. Their breath steams from a chest that no blade can pierce. Steel screeches and splinters against them, arrows crumple mid-flight, and every strike against their body is answered by the cold, unyielding truth of metal. In that moment, they are no longer merely mortal — they are a walking bulwark, a thunderous engine of war clad in unbreakable iron.

Level 3: Metallic Fury

When you enter Rage, you transform to become covered head to toe in flexible organic metal. This metal is unaffected by spell effects that target specifically metal. When you enter Rage and while your Rage is active, you gain the following effects that last for the duration.

Chromebound. Ignore your levels of Exhaustion below 6 and you don't require food, air or water.
Iron Fists. Your Unarmed Strike damage becomes equal to 1d8 plus your Strength modifier so long as you aren't holding any weapons or a Shield. This damage becomes 2d6 at Barbarian level 10.

Level 3: Metallurgy

You have a pool of Steel Points that you use to fuel Metallic Abilities that are listed below.

The Steel Point Table below shows your Steel Point maximum at key Barbarian levels.

Steel Point Table

Barbarian Level

Steel Points

3

3

6

4

10

5

14

6

You regain all expended Steel Points when you finish a Short or Long Rest.

Metallic Abilities
You gain the following Metallic Abilities.

Anvil Strike. You can expend 1 Steel Point to make an Unarmed Strike as a Bonus Action.
Reactive Alloy. When you take Acid, Cold, Fire, Necrotic, Poison or Radiant damage, you can expend 1 Steel Point to take a Reaction to reduce the damage by 1d12 plus your Barbarian level.
Siberian Express. When you take the Dash Action, you can expend 1 Steel Point to gain the ability to move through and thus destroy portions of walls that are less than 1 foot thick. Each wall passed through, uses 10 feet of movement.

Level 6: Galvanised

When you deal damage with an Unarmed Strike, it can deal your choice of Bludgeoning or Force damage.

In addition, when a creature you can see within 60 feet of you would take damage from a melee or ranged weapon attack, you can take a Reaction to move up to your Speed towards that target. If you are within 5 feet of the targeted creature after this movement, you can switch place with them to take the damage dealt instead. When you do, you can regain 1 expended Steel Point.

You can use this feature an amount of times equal to your Strength modifier before you must finish a Long Rest to regain all expended uses.

Level 10: Colossal Clinch

You gain access to the following Metallic Abilities.

Chrome Crush. When you successfully Grapple a creature one size larger or smaller than you and have both hands empty, you can expend 2 Steel Points to hold and choke them. When you do, the Grappled creature gains the Paralysed condition until the start of their next turn or until damage is dealt to them, after which, the Grappled condition ends for them.
Silver Slam. Once per turn, when you deal damage with an Unarmed Strike to a Large or smaller creature, you can expend 1 Steel Point to lift and slam that creature into the ground in one fluid motion. They must make a Dexterity saving throw against your grapple escape DC or take 4d6 plus your Strength modifier as Bludgeoning or Force damage and gain the Prone condition. On a successful save, they take half damage.

Level 14: Unstoppable Colossus

When you enter your Rage, you can expend an additional use of your Rage to increase your Steel Point maximum by 4 and gain that many Steel Points. Your Steel Point maximum is increased this way until your Rage ends.

In addition, when you deal damage with an Unarmed Strike, you can expend 1 Steel Point to double your Rage damage bonus during damage calculation.