Ninja Blade is a Primary Power Set for Stalkers.
You are an expert with the quintessential Japanese Middle Ages sword. Your blade is nearly -- or perhaps literally -- an extension of your own arm. While anyone with the requisite coordination can wield a Ninja Blade in combat, you've mastered stunts and maneuvers that most could not hope to match. You attack with surprising speed, and your cuts are deep and debilitating, often reducing your target's ability to defend itself for a few moments.
A Ninja Blade is a non-specific Japanese-style weapon, not much more than two feet in length, single-edged, and wielded with one hand. You make a melee attack roll to hit a target with it. As it is a finesse weapon, you may choose whether to apply your Strength or Dexterity Modifier to your attack and damage rolls. You may choose either at the time of attacking, but whichever Modifier you use for your Attack Roll must be the same one applied to your damage roll. You are also considered proficient with it, so you add your Proficiency Bonus to the attack roll. It deals slashing damage equal to 1d6 plus your Strength or Dexterity Modifier.
You are an unparalleled expert with your weapon. You are proficient with all forms of smaller, one-handed Medieval Japanese swords. For the purposes of this Power Set, a Ninja Blade is a shortsword (from the Dungeons & Dragons 5th Edition Player's Handbook).
You can also use your Action to make special maneuvers with your Ninja Blade. You can use Sting of the Wasp and Gambler's Cut at 1st level, Soaring Dragon at 10th level, and Golden Dragonfly at 12th level.
At 1st level, you can whirl your Ninja Blade in a tight cone 7 feet long and 10 feet wide. Each creature in that area must make a Dexterity Saving Throw. If it fails its Saving Throw, it takes 2d6 slashing damage and becomes vulnerable to slashing damage until the end of its next turn. If the Saving Throw is a success, the creature takes half damage but suffers no other effects.
Starting at 2nd level, you can take a moment to focus your senses. Roll at least one Endurance Die. You can add the result to every Ninja Blade attack and damage roll you make until the end of your next turn. Using this feature does not cost an Action but you can only do it on your turn.
At 7th level, whenever you are successfully hit by a ranged or melee attack roll, you can use your Reaction to parry the attack, taking no damage. If the attack roll is a critical hit, using this feature will convert it into a regular hit. You must be able to see your attacker.