Martial Archetype: Cut-Throat

A lightly-armored sellsword irritates an armored knight by dodging blows, tiring his opponent before striking home without fear of reprisal. A warrior in full plate trusts his cuirass to stop a savage cut as his own blade sends a head flying. A berserker uses a free hand to entrap a weapon arm and guts his enemy with vicious stabs of his shortsword.

These are the cut-throats, warriors without creed or code, the sellswords and the savages. No knightly apprenticeship or combat academy taught them battle, for they rise from the humblest origins and earn prestige though luck, wit and strength of arms. A cut-throat seizes the advantage at the moment it presents itself, knowing that to falter or gloat before the enemy is finished is to risk death oneself.

Combat Pragmatics

Beginning at 3rd level when you choose this archetype, you master a few tricks, techniques and quirks of fighting that work for you, if not for anyone else.

Dirty Trick. When you take the Attack action, you can replace one of your weapon attacks with an underhanded maneuver. Make a Dexterity (Sleight of Hand) or Charisma (Deception) check against the Passive Wisdom (Perception) of a creature within 5 feet of you. If you win this check, the creature's next attack roll has disadvantage and it cannot take reactions until the end of its next turn.
Insider Blading. You are particularly deadly in the chaos of close quarters. When you are grappling a creature, your attacks against it have advantage.
Rope the Dope. You bait your enemies into wild swings, always ready for an opportune strike. When a creature has disadvantage on its attack roll and misses you with an attack, you can use your reaction to make a melee weapon attack against it.

Street Schooled

Also at 3rd level, your mean upbringing grants you proficiency in either Sleight of Hand or Deception.

Not Today

At 7th level, you protect yourself in unconventional ways. You can use one of the following options as a reaction when you would be hit by an attack, but before the damage is rolled:

Humanoid Shield. If you are grappling a creature other than your attacker and it is size medium or smaller, you can move 5 feet into an unoccupied space without provoking opportunity attacks and pull the grappled creature into your vacated space. The creature becomes the target of the triggering attack instead of you.
Take the Blow. You know the strengths of your armor, redirecting strikes to where they do little harm. You reduce the attack's damage by the amount your AC exceeds 10, to a minimum of zero.

You can use these abilities a number of times, combined, equal to your Constitution modifier (minimum once) and regain all uses when you finish a long rest.

Cut Your Losses

Beginning at 10th level, you are adept at catching your breath and repositioning even in the heat of combat. When you use your Second Wind or Action Surge feature, you also gain the benefit of a Disengage action.

Cheap Shot Artist

At 15th level, when you hit with an attack for which you made the attack roll with advantage, add 1d6 to your damage roll.

Steal the Kill

Beginning at 18th level, when a creature you can see takes a critical hit, you can use your reaction to move up to your speed without provoking opportunity attacks and make one attack against that creature.

If this attack reduces the creature to 0 hit points, you can gloat about it as part of this reaction and gain temporary hit points equal to your fighter level.