Caesar Clown

Biodata

Feature	Value
Name	Caesar Clown (凯撒库朗)
Alias(es)	Caesar Crown; Caesar Kuro; “Expert in Weapons of Mass Destruction”; Roy’s First Scientist
Gender	Male
Affiliation	Roy’s Sky City and research organization
Occupation/Role	Director of Sky City’s Central Research Institute; weapons developer; Devil Fruit and clone researcher
Status	Active
First Appearance	39

Background / History

Caesar was formerly a World Government scientist stationed at Punk Hazard and was regarded as the world’s second-greatest scientist. His intellect and research ability delayed his transfer from Enies Lobby to Impel Down after he destroyed Punk Hazard’s restricted research zone with an explosion and poison gas. 29 39

The Punk Hazard incident was deliberate: Caesar intended to defect to Doflamingo, whose support would let him pursue Artificial Devil Fruit research and establish himself as the world’s greatest scientist. He arranged for a Doflamingo spy to smuggle him a wire lockpick during his transfer. 39

He escaped his Seastone restraints, hypnotized the warship’s guards with gas, and fled in elemental form. Roy intercepted him before he could meet Doflamingo, neutralized his abilities with Seastone-infused clouds, and forced his surrender through lethal intimidation. 40 41

Roy then made Caesar dependent on Sky City by fabricating a bounty claim that Caesar could read Poneglyphs, leaving him hunted by the World Government. Roy also took Caesar’s hair and nails to create a tracking Vivre Card, then gave him a large Sky City research institute and assigned him to the Seraphim project. 41 42

Appearance

Caesar is a scientist with a slicked-back hairstyle who commonly wears a white laboratory coat. He is later described as emanating purple energy while using his awakened gas abilities. 61 270 391

• Slicked-back hair. 61
• White scientist’s coat. 470
• Frequently carries chemical weapons, test tubes, and portable gas containers.
• Uses protective gear when handling potent experimental materials. 142

Personality

Caesar is arrogant, vain, and intensely competitive, particularly toward Vegapunk and Vinsmoke Judge. He repeatedly calls himself the world’s greatest scientist and seeks accomplishments grand enough to eclipse his rivals. 39 51 354 468

Despite his bravado, Caesar is cowardly when directly threatened by superior opponents. He favors escape, traps, poisons, and indirect warfare over close combat; Roy’s overwhelming force initially reduced him to submission. 40 41 92 215

His fear of Roy gradually becomes loyalty, professional pride, and a relationship resembling friendship. As Roy’s First Scientist, Caesar becomes comfortable speaking casually around him and takes personal responsibility for research essential to their organization’s expansion. 270 419 471

Caesar treats living beings as experimental resources. His fascination with modified beasts, cybernetic subjects, clones, and biological weapons often overrides concern for their suffering. 67 101 118 161

Abilities & Skills

Gas-Based Logia Devil Fruit

Caesar can transform into poisonous gas, fly, spread toxins through enclosed spaces, and conceal himself within chemical fog. His Devil Fruit abilities later fully awaken, greatly improving his combat capability. 40 391

• Elementalization and flight — Escaped a Marine prisoner ship by turning into gas and flying through gaps in its hull. 40
• Hypnosis Gas — Hypnotized the surveillance Den Den Mushi and guards during his escape. 40
• Poison Gas Impact — Projects a large volume of toxic purple gas directly at targets. 395
• Awakened power — By the Leviathan Base operation, his awakened abilities and self-modification had made him one of Roy’s strongest subordinates. 391
• Limit — Seastone particles suppress his Devil Fruit abilities and can force him out of elemental form. 40

Chemical Warfare

Caesar is an expert in lethal gases, chemical agents, anesthetics, and delivery systems. His toxins are designed for battlefield denial, delayed incapacitation, covert infiltration, and mass casualties. 60 65 66 212

• KX Poison Gas and KORO — Early Sky City weapons deployed against Golden Lion’s forces. 60 142
• Organophosphorus poison gas — Fired from a rocket launcher against the Flying Pirates and their Giant Beasts. 65
• Death Dioxide No. 1 — Reacts with existing toxins to make part of the gas colorless and odorless while amplifying toxins already absorbed by victims. 65
• Death Dioxide — A fully developed chemical weapon capable, under specific conditions, of affecting even Logia elementalization; its release at Marineford incapacitated combatants and formed hardened shells over victims’ bodies. 212 419
• Slowness Potion — A colorless, odorless muscle-relaxant derivative that slows a target’s senses; used to capture Marco. 93
• Neurotoxin Bombs — Released against the Beasts Pirates after the Onigashima explosion. 299
• Anesthetic and paralytic gases — Includes Death Dioxide No. 2 and a poison derived from a Deep Sea Stinger Octopus. 142

Scientific Research and Modification

Caesar specializes in weapons development, artificial Devil Fruits, biological engineering, cybernetics, cloning, and physical modification. He coordinates multiple research fields through Sky City’s Central Research Institute. 101 344 419

• Modified Golden Lion with mechanical brain structures and programming, preserving part of his combat ability and eventually achieving a 90% match to Bartholomew Kuma’s modified state. 78 179
• Modified Wapol with mechanical control systems and developed Wapol Metal, a memory material created through Wapol’s Munch-Munch Fruit. 101
• Led the semi-mechanical conversion of Samael, installing brain communications equipment and underwater weaponry. 118
• Participated in physical and memory modification procedures on powerful captives alongside Trafalgar Law and Brulee. 325
• Oversees Devil Fruit cloning, including fully mastered Zoan cloning and limited Paramecia cloning. 419
• Rapidly mastered most of the technology behind Second Birth, the serum that allows a person to possess two Devil Fruit abilities. 467

Large-Scale Weapon Development

Caesar’s signature field is the creation of weapons capable of changing entire battlefields or threatening nations. 39 419

• Created concentrated Explosive Rock weaponry and helped deploy it against Onigashima. 299
• Compressed and prepared Dyna Stones, weapons described as comparable to Ancient Weapons. 270 293
• Enhanced eight bombs used in the bombardment of Mary Geoise. 193
• Led the construction of the Black Sun, a colossal aerial weapon powered by Mother Flame energy and enhanced with Float-Float Fruit green blood. 424 453
• Completed the Black Sun, which was publicly revealed above the East Blue and was considered capable of rivaling or surpassing Ancient Weapons. 483

Technical and Medical Knowledge

Caesar’s intelligence extends beyond chemical warfare.

• Picked Seastone handcuffs and shackles with a wire tool during his escape from Marine custody. 40
• Maintained Golden Lion’s life through advanced medical technology before Trafalgar Law’s surgery. 73
• Recognized the limitations of his own Lineage Factor knowledge when studying the Seraphim project, particularly Vegapunk’s ability to combine multiple Lineage Factors. 51
• Developed elite Den Den Mushi capable of functioning in harsh environments. 75
• Gained enough physical strength through training and self-modification to lift tens of tons. 395

Equipment / Weapons / Items

• Poison gas bombs and organophosphorus rocket launchers. 61 65
• Death Dioxide chemical agents and delivery systems. 65 212
• KORO and KX poison gas. 60 142
• Slowness Potion test tubes. 93
• Neurotoxin Bombs and Concentrated Explosive Rock. 299
• Protective suit for handling high-risk chemical materials. 142
• Elite Den Den Mushi engineered for harsh environments. 75
• Floating Aircraft Carrier used for major research and transport missions. 468

Relationships

• Roy — Former captor and current leader. Roy forced Caesar’s submission, created a Vivre Card from his hair and nails, and made him dependent on Sky City; over time, their relationship developed into trust and casual familiarity. 41 42 270 471
• Vegapunk — Former colleague and primary scientific rival. Caesar envies Vegapunk’s Lineage Factor expertise but later gains authority over him after Vegapunk agrees to serve as his assistant and clone the Brain-Brain Fruit. 51 354
• Vinsmoke Judge — Rival scientist and eventual collaborator. Judge seeks to surpass Caesar, while Caesar recruits him for cloning, battle-suit technology, and Lineage Factor research. 354 419 468
• Queen — Fellow scientist and collaborator on bacterial weapons and modifications; Queen is also subordinate to Caesar within Roy’s research structure. 354 419
• Kuzan — Combat partner who protected Caesar from Giant Beasts during the Floating Island conflict. 61 65
• Golden Lion — Former enemy turned long-term experimental subject and modified weapon under Caesar’s programming. 69 78 179
• Enel — Former test subject who fears Caesar’s experiments. Enel later saves Caesar from the combined attack of three Admirals at Marineford. 161 215
• Trafalgar Law — Medical collaborator whom Caesar initially distrusted but later respected after Law successfully operated on Golden Lion. 73
• Wapol — Mechanically controlled experimental subject used to produce silver and develop Wapol Metal. 101
• Slockscaranz — Subordinate with the Shrink-Shrink Fruit who assisted Caesar in stealing and transporting Sunstones. 395

Story Role / Major Arcs

Punk Hazard and Escape

• Causes the Punk Hazard disaster, is imprisoned at Enies Lobby, and is scheduled for transfer to Impel Down. 29 39
• Escapes with Doflamingo’s assistance but is intercepted, defeated, and recruited by Roy. 39 40 41
• Receives a Sky City laboratory and begins researching the Seraphim project. 42

Sky City Scientist

• Develops poisons and tactical chemical weapons during the battle against Golden Lion’s Flying Pirates. 60 65 66
• Helps preserve, alter, and weaponize Golden Lion after his defeat. 69 73 78
• Modifies Wapol and Samael into controlled industrial and military assets. 101 118

Marineford and Global Operations

• Uses Death Dioxide to devastate Marineford, forcing Marines and pirates alike to contend with widespread toxin exposure. 204 212
• Is targeted by three Admirals after being exposed as the Punk Hazard poison-gas mastermind, but Enel rescues him. 215
• Leads operations to steal Dyna Stones from a Marine base alongside Golden Lion. 270 272
• Develops weapons used against Onigashima, including Explosive Rock and Neurotoxin Bombs. 299

First Scientist of Sky City

• Oversees Artificial Devil Fruit production, improving the fruits until their former severe side effects are removed. 321
• Gains elite criminal scientists from Impel Down as assistants, accelerating projects in biology, mechanics, genetics, cloning, weapons, and Devil Fruit research. 344
• Formally reports responsibility for Devil Fruit cloning, destructive weapons, and Lineage Factor/clone optimization, cementing his status as Roy’s First Scientist. 419

Black Sun and Second Birth

• Helps develop and implement Second Birth, then supervises Roy’s successful acquisition of a second Devil Fruit ability. 467 469 470
• Accelerates Black Sun’s final testing after fearing that Vegapunk, Judge, and Queen may surpass him. 468
• Completes the Black Sun, securing a weapon whose power establishes his scientific supremacy within Roy’s organization. 483

Notable Quotes

“I am the authority on large-scale lethal weapons!” 66

“I, Caesar Clown, will absolutely not let you down. Just wait until you ascend the throne of the King of the World!” 471

Trivia

• Caesar’s fabricated Poneglyph-reading bounty was set at 700 million Belly. 41
• His extensive experimental waste and failed chemical projects contributed to Sky City’s aerial “junkyard,” whose accumulated toxins became comparable to purpose-built chemical weapons. 157
• His greatest ambition is to surpass Vegapunk and be recognized as the world’s greatest scientist. 39 354 468