Headsman

The archetypal Headsman is a soldier of ruthless execution. A monstrous warrior, with little to no regard for their own safety and health. For their only thought is to persecute; hound and destroy the enemy, even at the cost of their own lives. Those who model themselves on this archetype rely on brutality and fear tactics to overcome their obstacles. However, their strength does not come from rage or hatred, but from their own pain, and their will to cause as much as they receive. Honor is not often in their vocabulary, but efficiency is.

Headlong Charge

Beginning when you choose this martial archetype at 3rd level, you gain the ability to cut through swaths of enemies with one swing. When you hit a target with a melee attack, you can choose another creature within 5 feet of the original target and within your reach. The damage dealt by your attack is evenly divided between the two creatures.

Additionally, each time you gain a feature in this subclass, you can apply this effect to additional creatures: two creatures at 7th level, three creatures at 10th level, four creatures at 15th level, and five creatures at 18th level.

You can only apply this feature to one attack per turn, and any additional effects that take place as a result of hitting an attack only affect the original target.

Brutality

Additionally at 3rd level, you learn how to make your melee attacks especially punishing. Whenever you are wielding a weapon with the two-handed or heavy property, you can, at the start of each of your turns, decide to enter Brutality until the end of this turn. While in Brutality, all two-handed or heavy weapon attacks that use Strength deal additional damage equal to your Strength modifier + your Constitution modifier. Additionally, while in Brutality, your speed is halved, and you have disadvantage on Dexterity and Constitution saving throws until the end of your next turn.

You can only enter Brutality a number of turns equal to your Strength modifier (minimum of 1). You regain all expended uses of this ability at the end of a long rest.

Constrained Savagery

Starting at 7th level, you gain the ability to tactfully withhold your destruction. Whenever you roll a critical hit on the d20, you can choose to instead treat that attack as a miss. For the next hour, your critical hit is stored for later use. Within the next hour, you can choose to consider any one attack you make on your turn as a critical hit.

Bloodied Assault

Beginning at 10th level, you can purposefully over-exert yourself in order to debilitate your foes. Expending either an action or one of your attacks, you take an amount of necrotic damage equal to your fighter level + your Constitution modifier, and your hit point maximum is reduced by the same amount. On this turn, when you hit another creature with an attack, you can choose to have that attack deal no damage, and instead attempt to make the target either Blinded, Frightened, or Prone (your choice). The target must make a Constitution saving throw, against a DC equal to  8 + your proficiency bonus + your Strength or Dexterity modifier (your choice). On a failed save, the target gains the condition of your choice until the end of your next turn.

Reductions to your hit point maximum suffered by this ability last until the end of your next short or long rest. Additionally, necrotic damage dealt by this ability ignores any resistances or immunities.

Ruthless Efficiency

At 15th level, you have mastered the art of making your attacks ruthlessly efficient. On each of your turns, per action, you can choose to have one attack you make ignore the target’s damage resistances, and treat the target’s immunities as if they were resistances. You choose which attack the ability applies to before it is rolled.

Tortuous Will

At 18th level, you have trained to where you can turn your pain into that of your enemies’. Whenever your current hit points are below half your hit point maximum (rounded down), you can use your bonus action to make one additional attack. Additionally, whenever you are below one quarter of your hit point maximum, each critical hit you make causes the target to take 1 point of exhaustion.