Dread Knight - 5E Fighter Subclass

Dreadful Surge

When you choose this archetype at 3rd level, you gain the ability to invoke terror in your enemies.

When you use your Action Surge feature, all creatures you choose within 15 feet must make a Wisdom saving throw with DC = (8 + your proficiency bonus + your Constitution modifier). On a failed save, creatures are frightened, and make a Wisdom saving throw at the end of their turn to remove this effect.

Emissary of Fear

At 7th level, you gain proficiency in the Intimidation skill. In addition, your proficiency bonus is doubled for any ability check you make that uses Intimidation.

You also gain advantage on Wisdom saving throws.

Resurgence

At 10th level, you become especially hard to kill, a true knight of fear and conquest. When you use your Second Wind feature, you gain temporary hit points equal to the health healed, and until the end of your next turn all attacks have disadvantage to hit you.

Implacable

Starting at 15th level, your enemies cannot deny your dreadful power. If you would roll with disadvantage on an attack roll or skill check, roll without disadvantage instead.

Iron Will

Starting at 18th level, even the mightiest of magics shatter against your unbendable will. You have advantage on saves against spells and other magical effects.

Closing Notes

• One of my earlier homebrews that I'm not entirely sold on now. But I'm not entirely against it either.
• Basically the Black Knight archetype. Whether that means Fire Emblem's extremely persistent and unstoppable warrior or Monty Python's extremely persistent but very stoppable warrior is up to you.
• Lots of mechanics ripped from the P*rple Dragon Knight, though being able to use Action Surge offensively seems like a better idea just because you're usually already trying to kill your enemy with it.
• Sometimes you want to have the aesthetic of a Oathbreaker or Conquest Paladin but not the whole magic thing.