William

Biodata

Feature	Information
Name	William / Dragon D. William 49 253
Alias(es)	“Demon Dragon” William 218 241
Species/Race	Human; an Earth transmigrator inhabiting the original Marine Colonel William’s body 1 264 564
Gender	Male
Age	19 at the time of his profile entry 49
Affiliation	Straw Hat Crew; commander of the Castle Army; formerly a Marine Colonel and Revolutionary Army undercover agent 49 92 253
Occupation/Role	Strategist of the Straw Hat Crew 49 253
Devil Fruit	Lizard-Lizard Fruit, Model: Castle Dragon — Mythical Zoan 3
Bounty	400,000,000 Beli, as reported after the Cake Island conflict 501
Status	Active
First Appearance	1

Power Progression

Stage / Realm / Level	Chapter	Notes
Marine and Revolutionary foundation	49	The original William learned Dragon Claw Fist under Monkey D. Dragon, trained in Armament and Observation Haki under Zefa, mastered the Six Powers, and refused a CP9 reserve nomination.
Castle Dragon Fruit acquired	2 3	Ate the Devil Fruit he was assigned to escort. Initially mistook it for the Castle-Castle Fruit before identifying it as an unrecorded Mythical Zoan with an internal castle.
Silent Six Powers, Dragon Flame, and Four-Sword Style	31	Integrated Kuro’s Silent Step into Shave and Moon Walk; developed fire breath and adapted Two-Sword Style plus Rankyaku into Four-Sword Style.
Zoan awakening and loss of control	110 122	Awakened the Castle Dragon Fruit, but its demonic nature overwhelmed his mind and turned him into a red-hot berserker.
Four Enhancements and Life Return healing	133	Gained Brain Point, Strength Enhancement, Speed Enhancement, and Leather Armor Enhancement; developed rapid cellular recovery through Life Return.
Haki Stacking	213 214	Began combining the Castle Army’s Armament Haki with his own to survive attacks from Commander-in-Chief Kong, though even the full force could not sustain a prolonged fight.
Demonic Aura: Dragon’s Might	259	Manifested damaging demonic pressure capable of collapsing Monet’s Snow Giant and preventing her Logia elementalization, but initially harmed allies as well.
Expanded Six Powers derivatives	293	Created Finger Pistol: Piercing Finger, Finger Pistol: Air Slice, and close-range Fist Pistol through swordsmanship training.
Army-assisted Armament techniques	424	Used the Castle Army’s Haki for Armament: Leg Gun and Armament: Wheel Bullet, overwhelming Doflamingo at considerable physical cost.
Armament Mode and high-level Emperor combat	562 567 579	Maintained a Castle Space domain fueled by allies’ Armament Haki, fought Kaido directly, and used Demonic Aura to reduce Kaido’s vitality and regeneration.

Background

The original William was born somewhere on the Grand Line and was raised as an undercover Revolutionary Army asset. He entered the Marine Headquarters academy at age one, became a disciple of Monkey D. Dragon, and later trained under former Admiral Zefa alongside Estamba Cheng. By sixteen, he had mastered the Six Powers, received Haki instruction, and declined a place in CP9. He later served as Vegapunk’s bodyguard and rose to Marine Colonel. 49

An Earth soul transmigrated into William’s body aboard a Marine warship in the East Blue. With none of the original owner’s memories or combat instincts initially accessible, he maintained the intimidating facade of “Colonel William” while trying to survive. 1 4 He ate the Devil Fruit assigned for delivery to the Celestial Dragons, then learned that the fruit’s loss would likely result in execution or enslavement. He chose desertion rather than submission. 3 4

After being stranded at sea, William encountered Monkey D. Luffy. He initially resisted becoming a pirate, but his duel agreement with Luffy and their shared pursuit of freedom led him to join the Straw Hat Crew. 6 92 513

Appearance

William commonly conceals his identity with a baseball cap and damaged mask, especially when operating independently. His awakened Mythical Zoan grants several visually distinct forms. 66 289 302

• Brain Point — His normal human form; an additional eye appears on his forehead, reflecting heightened intelligence and perception. 133
• Strength Enhancement — A muscular humanoid lizard form focused on physical power. 132 133
• Speed Enhancement — A roughly two-and-a-half-meter humanoid lizard form with reduced air resistance and increased leg strength. 133
• Leather Armor Enhancement — A large beast form with greatly enhanced durability and hardened hide. 133 249
• Rampaging awakened form — A red-hot beast-man state with bloodshot eyes, extreme regeneration, and no recognition of allies. 122

Personality

William began as a fearful but practical survivor. Lacking the original body’s memories, he bluffed subordinates, avoided revealing weaknesses, and preferred escape over hopeless confrontations. He considers fighting a vastly superior enemy without a purpose to be stupidity rather than bravery. 4 214

He is calculating in battle, relying on traps, misdirection, reconnaissance, and the hidden Castle Army rather than public displays of strength. He is willing to eliminate witnesses or use intimidation when operational security demands it, particularly against agents of the Celestial Dragons. 239 246 318

Despite his pragmatism, William repeatedly risks himself for companions and victims of oppression. His pursuit of power gradually shifts from personal survival to protecting the people and dreams important to him. 213 249 501 He remains fiercely loyal to Luffy and rejects any path to Pirate King that does not place his captain first. 92 357

Abilities & Skills

Lizard-Lizard Fruit, Model: Castle Dragon

William’s Mythical Zoan combines dragon transformations with an internal castle ability resembling the Castle-Castle Fruit. The fruit is unrecorded in the Devil Fruit Encyclopedia. 3

• Grants human, hybrid, and beast transformations, later refined into four awakened specialized forms. 3 133
• Allows William to create and command Castle Space, an internal environment that can house people, weapons, supplies, prisoners, and military equipment. 2 3 479
• Enables Castle Domain, transferring nearby allies or enemies into Castle Space and deploying the Castle Army onto a battlefield. 150 214
• His strength scales with the Castle Army’s troop numbers, equipment, and Haki support. 253
• Seastone and immersion in the sea remain critical weaknesses. 2 122

Awakened Enhancements

Form	Specialization	Notable traits
Brain Point	Intelligence and observation	Restored the original William’s memories and substantially improved mental processing. 133
Strength Enhancement	Raw power	A muscular lizard-man form used for heavy strikes and close combat. 132 133
Speed Enhancement	Mobility and leg strength	Supports high-speed evasions, silent movement, and Moon Walk escapes. 133 214
Leather Armor Enhancement	Defense	A hardened beast form capable of enduring heavy physical attacks. 133 249

Castle Army and Haki Support

William can use the soldiers within Castle Space as a distributed combat force and source of support.

• Haki Stacking combines the Armament Haki of Castle Army members with William’s own Haki. 213
• Armament Mode requires a continuous supply of allied Haki, allowing him to contend with enemies such as Kaido and Edward Weevil. 562 575
• The transfer is inefficient: more than thirty percent of the supplied Haki can be lost in the process. 243
• Sustained Haki Stacking severely strains William’s body and cannot close the gap against every top-tier opponent. 214 424

Demonic Aura: Dragon’s Might

Demonic Energy is a pressure-based power distinct from Conqueror’s Haki. Baozi considers it comparable to top-tier Conqueror’s Haki because it can inflict direct damage. 253

• Prevents affected Logia users from elementalizing. 259
• Can disrupt souls, as demonstrated by separating Big Mom’s power from Zeus and Prometheus. 484
• Causes spatial vibrations and damages living creatures internally. 448
• Rapidly drains vitality and interferes with regenerative abilities, including Kaido’s Life Return and Zoan recovery. 567 568
• Initially affects allies and enemies indiscriminately, causing unconsciousness, nightmares, and collateral danger. 259 261

Six Powers and Life Return

William’s mastery of the Six Powers is adapted for assassination and silent movement. 49 142

• Silent Shave / Silent Moon Walk — Integrates Kuro’s Silent Step, allowing nearly soundless high-speed movement. 31 142
• Iron Body: Jade — A hardened-body technique used to strike through defenses. 142
• Rankyaku — Used as aerial slashes, foot blades for Four-Sword Style, and techniques such as Lizard Turret. 31 133
• Finger Pistol derivatives — Includes Piercing Finger, Air Slice, Crimson Lotus, and Fist Pistol techniques. 292 293
• Life Return: Healing — Directs consciousness into his cells to rapidly heal injuries. 133
• Water Walking — A self-created combination of Shave and Moon Walk that permits rapid movement across the sea’s surface. 303

Swordsmanship and Dragon Claw Fist

William inherited Two-Sword Style training and developed it into Four-Sword Style by using Rankyaku as two additional blades. 2 31

• Uses Two-Sword Style, Four-Sword Style, and techniques including Great Tornado, Crossfire Slash, Siege Cannon, and Steel-Cutting Technique. 242 246
• Trained in Dragon Claw Fist under Monkey D. Dragon. 49
• Dragon Claw Fist: Dragon’s Breath destroyed the cyborg Rick’s internal components. 243
• Can breathe fire in dragon forms, including Dragon Flame: Cannon and Dragon Flame Fire Fist. 31 484
• Developed Taiji techniques and Pressure Point Strikes during the two-year training period. 567 601

Equipment

• Muramasa — Supreme Grade Blade acquired on Weapon Island. 66
• Dragon Spring — Supreme Grade Blade forged by the Ouji Swordsmith Family. 66 156
• Castle Space arsenal — Stores firearms, laser cannons, ammunition, supplies, and captured equipment. 66 117 213
• Mask and baseball cap — Used to conceal his identity during independent operations. 66 289 302
• Glider — Used to travel from Mary Geoise to Marineford while conserving stamina. 218

Relationships

• Monkey D. Luffy — Captain and closest political allegiance. William joined after their early East Blue encounter and has repeatedly stated that only Luffy will become Pirate King. 6 92 513
• Monkey D. Dragon — Original William’s Revolutionary Army mentor; taught him Dragon Claw Fist and introductory Haki. 49
• Zefa — Former Marine instructor who trained William in Haki and the Six Powers. William retains concern for him despite leaving the Marines. 49 297
• Drake — Former superior who taught William Two-Sword Style. Their shared past belongs largely to the original William’s recovered memories, leaving the transmigrated William emotionally distant. 4 195 564
• Baozi / Francis Bo — Adviser, mentor, and senior Castle Army combatant. Baozi pushes William to develop Demonic Energy and use the Castle Army as his true strength. 156 253
• Nojiko — Castle Army member and trusted observer who frequently supports William with intelligence and battlefield warnings. 33 424
• Estamba Cheng — Former Marine academy classmate and fellow Zefa disciple. She investigated his disappearance and later cooperated with him during the Fish-Man Island crisis. 49 400
• Koala — Trusted ally with Revolutionary Army ties who participates in William’s operations and helps coordinate the Castle Army. 214 245
• Boa Hancock — William saved her during the Buster Call on Amazon Lily; she became immediately infatuated with him. 616
• Roberts D. Sanbao — Fellow Earth transmigrator, rival, and uneasy Straw Hat Alliance partner. William values both his strength and his knowledge of altered events. 89 415

Story Role / Major Arcs

• Marine defection and East Blue — Eats the Celestial Dragons’ Devil Fruit, abandons the Marines, meets Luffy, and begins traveling with the future Straw Hat Crew. He later confronts Arlong to protect Cocoyasi Village’s residents. 3 6 33
• Sky Island and Enies Lobby — Develops Silent Six Powers, awakens his Zoan power, defeats Kumadori, and helps rescue Nico Robin despite the Buster Call. 31 122 142 145
• Mary Geoise and Summit War — Frees thousands of slaves, escapes Commander-in-Chief Kong, infiltrates Marineford, and frees Ace from Seastone restraints. 213 214 218
• Two-year separation — Trains intensively, develops the Castle Army, joins Revolutionary Army operations, and eventually arranges for the SG Legion to remain behind rather than continue as pirates. 160 245 270
• Dressrosa and Straw Hat Grand Fleet planning — Battles the Poker Army, confronts Doflamingo, and secretly recruits Roberts D. Sanbao toward an expanded Straw Hat alliance. 292 415 424
• Whole Cake Island conflict — Uses Castle Space to capture Cracker, faces Smoothie and Big Mom, and supports the effort to retrieve Sanji. 481 484
• Wano conflict — Uses Armament Mode, Demonic Aura, Four-Sword Style, and Dragon Claw Fist in the alliance’s battle against Kaido. 562 567 579
• Amazon Lily Buster Call — Appears masked to rescue Boa Hancock and organizes the evacuation of Amazon Lily’s civilians through mirror clones. 616

Notable Quotes

“My fate is mine to control!” 160

“We only want to protect the things we want to protect!” 249

“I’m Dragon D. William, the future Pirate King’s strategist!” 253

Trivia

• William’s name is based on William Dampier, the English pirate, scholar, and explorer. 1
• He initially believed his power was the Paramecia Castle-Castle Fruit because Castle Space closely resembles Capone Bege’s ability. 2 3
• Although he is a capable Four-Sword Style fighter, William insists that he is not truly a swordsman and merely “happens to know how to use swords.” 447