How to Run Haki in a One Piece Campaign
Haki is the “spiritual willpower” of living beings, a force that transcends Devil Fruits. It’s rare in the Blues, more common in the Grand Line, and expected in the New World. Treat it as both a power system and a narrative milestone — players learning Haki means they’ve become true contenders on the seas.
Lore: The ability to sense intent, emotions, and predict movements. Skilled users can even “see” into the near future.
Basic Mechanics:
Early Game: Advantage on Perception/Insight checks.
Combat: Spend a Reaction to impose Disadvantage on one attack made against you.
Advanced:
Precognition (predict one enemy’s action before they declare it).
Sense hidden presences, even cloaked or invisible.
DM Tip: Use it to reward awareness. A player with Observation Haki should “feel” ambushes, notice lies, or sense killing intent. Don’t overuse future-sight — save it for high-tier foes.
Lore: Weaponizing willpower as an invisible (or blackened) armor. Lets users hit harder, block stronger, and bypass Devil Fruit defenses.
Basic Mechanics:
Early Game: Declare use before attacking → attacks count as magical and deal +2 damage.
Defense: Once per round, reduce incoming damage by 1d6.
Advanced:
Full Armament: Ignore resistance and immunities (e.g., Logia intangibility).
Internal Destruction: Deal damage directly to inside of target (ignores AC).
DM Tip: Introduce this as a counter to Logias and “tank buster” abilities. Marines and bounty hunters may use it to avoid players steamrolling encounters.
Lore: The rarest type, possessed only by “kings.” Allows the user to project their willpower to dominate others.
Basic Mechanics:
Once per Long Rest: Force enemies within 30 ft. to make a Wisdom save (DC = 8 + proficiency + Charisma). On fail → they are stunned/unconscious (weaker foes auto-fail).
Strong enemies resist with advantage.
Advanced:
Infuse attacks with Conqueror’s → once per short rest, a hit deals double dice damage.
Passive presence: Weaker NPCs collapse or refuse to fight before combat even starts.
DM Tip: This should always be cinematic. Conqueror’s is not “spam stun,” it’s an event. When used, describe entire rooms freezing, glass shattering, or animals bolting. It signals a major power jump.
East Blue (0–10 sessions): Almost no Haki. Maybe a Marine Captain or legendary bounty hunter has it.
Paradise/First Half Grand Line: Observation and Armament show up among mid-tier enemies. A few villains will crush rookies with it.
New World: Haki is standard for any strong foe (Supernova, Warlords, Admirals, Yonko). At this point, PCs should be expected to have at least one color.
Progression Rule of Thumb:
Observation → unlocked through survival and instinct.
Armament → unlocked through constant combat and need to “hit harder.”
Conqueror’s → either innate (chosen in backstory) or unlocked during a “willpower climax” scene (e.g., defying a Yonko, rallying an army).
Grunts & Minors: No Haki.
Captains/Officers (50M–200M bounty): Basic Observation or Armament.
Big Names (200M+): At least one advanced form.
Legends (Admirals, Yonko, Warlords): Multiple types, advanced use.
Foreshadow: Describe how strong characters feel oppressive even before fighting (hinting at Conqueror’s).
Player Growth: Let PCs first lose to Haki, then train to get it themselves.
Flavor: Make it personal — Observation feels like instincts sharpening, Armament feels like fists hardening, Conqueror’s feels like commanding the world itself.