Garrote Adept

You have mastered the art of garroting a foe from behind.

Using a garrote--such as a bowstring or wire to which you have added handles--you can attack a surprised humanoid or similar creature from behind and attempt strangulation. The target creature may be no more than one size category larger than you and must have a neck through which it draws air into its lungs.

Make a melee attack roll with advantage, adding your proficiency bonus and either your strength or dexterity bonus, attempting to wrap your garrote around the creature's neck and use the leverage of position to strangle the target. 

• On a hit, the target takes 1d4 (plus your strength bonus) bludgeoning damage, is grappled, and cannot breath.
• At the end of each of its turns, the target may make a Strength saving throw contested by your Strength (athletics) or Dexterity (acrobatics) check. If the target is your size or smaller or has 50% or less of its maximum hit points, it has disadvantage on this roll. On success, the grapple ends.
• Since you are grappling the target from behind, the target makes attacks against you with disadvantage.
• While this grapple lasts, the target automatically takes 1d4 (plus your strength bonus) bludgeoning damage each round, and you cannot take additional actions or reactions that require your hands.
• After being grappled in this way for a number of minutes equal to 1 plus the target's constitution modifier (minimum 30 seconds), the target drops to 0 hit points.

If your target is wearing a gorget, mail coif, or other armor protecting its throat, it can be grappled with this technique, but it takes no damage, is immune to strangulation, and is not disadvantaged on saving throws to escape.