Staff Fighting is a Primary Power Set for Brutes, Scrappers, and Stalkers, and a Secondary Power Set for Tankers.
You are an expert with the quintessential quarterstaff. While anyone with the requisite strength can wield a staff in combat, you've mastered stunts and maneuvers that most could not hope to match. You strike at your foes in sweeping arcs and swift, precision jabs. You can also learn various combat stances that allow you to strike more effectively, quickly, or efficiently.
A Staff is a blunt weapon capable of being wielded with one hand or two. You make a melee attack roll to hit a target with it, to which you add your Strength Modifier. You are also considered proficient with it, so you add your Proficiency Bonus to the attack roll. If you use it one-handed, it deals 1d8 bludgeoning damage. With two hands that damage is 1d10. In either case, you add your Strength Modifier to the damage. It has a melee reach of 10 feet, which may be overridden by specific features.
You are an unparalleled expert with your weapon. You are proficient with all forms of blunt pole arms. For the purposes of this Power Set, a Staff is a quarterstaff (from the Dungeons & Dragons 5th Edition Player's Handbook).
As a Staff Fighting expert, you always strive to excel with your skills. When conditions are right, you find yourself in a heightened state off Staff Fighting effectiveness called Perfection. You achieve Perfection whenever you make a critical attack roll with one of your Staff Fighting features, or cause enough damage to bring a creature to 0 hit points and render it incapacitated using a Staff Fighting feature. Once acquired, you retain your state of Perfection until the end of your turn on the round following the current one. Thus, if you begin your turn with Perfection and gain it again during that turn, the new application will last until your next turn.
While you are in a state of Perfection, you gain advantage on all Staff Fighting melee attack rolls, Dexterity Checks, and Dexterity Saving Throws. Your Eye of the Storm and Sky Splitter features are also affected by Perfection, depending on which Staff Mastery stance you are in.
You can use Mercurial Blow at 1st level, Eye of the Storm at 2nd level if you are a Brute or a Scrapper, at 6th level if you're a Tanker, and at 8th level if you are a Stalker. You can use Innocuous Strikes at 10th level if you are a Brute or Scrapper, and at 14th level if you're a Tanker, and Sky Splitter at 12th level if you're a Brute, Scrapper, or Stalker, and at 15th level if you're a Tanker.
At 1st level, when you are hit by an attack roll, you may use your Reaction to swing your Staff in a cone 7 feet long and 10 feet wide, oriented at the direction the attack came from. Roll 1d10 plus at least one Endurance Die and subtract that from your attacker's damage roll. If you reduce the damage to zero and there is at least one point of damage left over, any creature within the area of this feature must make a successful Dexterity Saving Throw or take that amount of damage as bludgeoning.
At 3rd level if you're a Brute or Scrapper, or at 8th level if you are a Tanker, your mastery of your Staff has reached new heights. On your turn, you can adopt one of three possible stances: Form of the Body, Form of the Mind, or Form of the Soul. Adopting or changing a stance does not cost an action but you can only do it on your turn, and only once per turn. If you change your stance, it must be the first thing you do on your turn. Each stance grant an inherent benefit, plus benefits applied to Eye of the Storm and Sky Splitter when you are in a state of Perfection.
While Staff Mastery is not available to Stalkers, upon reaching 3rd level a Stalker will have the permanent benefits of Form of the Body.
At 3rd level if you are a Stalker, you can take a moment to focus your senses. Roll at least one Endurance Die. You can add the result to every Staff Fighting 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. This feature is not available to Brutes, Scrappers, or Tankers.
At 7th level if you're a Brute or Scrapper, or at 10th level if you're a Stalker, or at 11th level if you are a Tanker, you can use your Action to make a single Staff attack at range. You may extend your Staff's length, or project a pseudo-physical ray of force, or even throw your Staff (and have it return to your hand). Regardless of how you do it, make a ranged Attack roll against a creature within 40 feet. You deal your normal two-handed damage but you use your Dexterity Modifier in place of your Strength Modifier.