Mousse

Biodata

Feature	Details
Name	Charlotte Mousse (慕斯)
Alias(es)	Locke; Tengtianxiao 142 265
Species/Race	Human
Gender	Male
Affiliation	Charlotte Family; BIG·MOM Pirates
Occupation/Role	Scientist, inventor, strategist, intelligence-network manager
Status	Alive
First Appearance	Chapter 1

Power Progression

Stage / Realm / Level	Chapter	Notes
Book-Book Fruit user	2 3	Gains control over books and can instantly memorize the contents of any book he touches.
Creation of Big Head	36 40	Creates the Poneglyph-based Homie Big Head, a unique fusion involving the Soul-Soul Fruit, Book-Book Fruit, and an indestructible stone tablet.
Data-type Observation Haki	62 64	His Observation Haki begins displaying numerical information, allowing him to quantify Haki and vitality.
Power Level 1	87	Reaches a measurable physical Power Level after sustained scientific training.
Power Level over 3	144 145	Can effectively use ordinary handguns, though powerful specialized firearms remain beyond his physical limits.
Big Head at supersonic speed	158	After studying Ohara's library, develops Big Head enough for it to surpass the speed of sound.
Power Level over 10	230	Continues rigorous physical training before age nine.
Soul Capture against top-tier opponents	240	Captures King's soul from range, placing himself among top-tier fighters despite his comparatively fragile body.
Power Level over 300	292	Masters Soru and Geppo through exceptional body control and Observation Haki.
Book-Book Fruit awakening	330	Gains the ability to strip and transfer powers, alongside access to further abilities through his Book World.
Power Level over 3,000	356	Reaches a level of physical strength and stamina sufficient to synchronize a powerful Homie with his own combat capability.

Background / History

At six years old, Mousse was offered the Book-Book Fruit by his elder brother Perospero. Before eating it, he insisted on taking and preserving a blood sample so he could compare his body before and after consuming a Devil Fruit. His mother, Charlotte Linlin, showed him unusual patience and favoritism, even during circumstances in which she would normally become enraged 1.

After consuming the fruit, Mousse revealed that it allowed him to instantly memorize the contents of books. While Linlin initially considered the ability useless, Perospero recognized its value and predicted that Mousse could become an exceptional scientist 2 3.

Mousse quickly turned his attention toward research into Linlin's abnormal physique, resilience, and gigantification. He sought genetic samples from Linlin's parents to compare against hers, both to understand her condition and to find a path around his own mediocre natural physique 4.

He later became a central planner within the Charlotte Family, advising siblings on Devil Fruit development, Haki training, military strategy, finance, intelligence gathering, and technological projects. By age twelve, Linlin had entrusted Whole Cake Island's intelligence network to him, making him one of its most influential figures 22 89 94 265.

Appearance

Mousse is a young human boy whose facial features are described as exceptionally flawless. During his stay in Ohara, he shaved his head; by the time he was recognized later, his hair had grown back 2 146 167.

• Small stature and initially frail physical build 40 144.
• Often travels using Big Head or flight devices rather than conventional ships 139 193.
• Uses compact concealed handguns designed for his own physical limitations 144.

Personality

Mousse is analytical, ambitious, and unusually mature for his age, shaped by memories from before his transmigration. He approaches powers, people, and political situations as systems to be studied, tested, and exploited. His research is driven not only by curiosity, but by a desire to overcome his weak physique and ensure his own safety 4 89 90.

He values rationality, competence, and predictability. He readily supports family members and allies who are willing to learn, including Katakuri, Custard, Brulee, Robin, and the Mink Tribe. He also has a strong inclination toward teaching, often turning his observations into practical advice for others 7 90 145 266.

Mousse can be compassionate when it serves his values or attachments, such as preserving Sabo in the Book World and training Nico Robin. However, he is also pragmatic and ruthless toward enemies, using Soul Search, power stripping, and lethal force without hesitation when he considers someone an obstacle 145 247 270 330.

Abilities & Skills

Book-Book Fruit

Mousse's primary Devil Fruit allows him to control books and treat recorded information as something he can directly access and organize.

• Instantly memorizes the contents of any book he touches 3.
• Uses rapid reading and structured memory layers to process enormous volumes of information 152 158.
• Can create and manipulate books as platforms for unstable emergency flight 193.
• Cannot use the fruit to directly decipher or extract the secrets of Poneglyphs 39.
• Experiences mental fatigue after sustained high-speed reading 142.

Book World

Mousse can use a Book World to contain consciousnesses and preserve their condition.

• Time does not progress inside the Book World, allowing him to prevent Sabo's injuries from worsening 308.
• Can capture souls and place them into constructed plot worlds under his control 240 252.
• Can erase or alter memories of those held in his Book World 252.
• Soul Capture is effective against unstable soul-derived constructs, including Gecko Moria's zombies 348.

Awakened Book-Book Fruit

Mousse awakened his Devil Fruit after using its memory-management functions to investigate hidden memories affected by the Hobby-Hobby Fruit 330.

• Can strip implanted powers from one person and transfer them to another 330.
• Gains abilities such as invisibility and teleportation through awakened functions 330.
• Can select one usable character from each of twenty-four plot sub-worlds per day and access that character's usable abilities 341.
• Cannot freely access every ability at once; the daily selection limit, world rules, preparation, and his mental strength restrict the technique 341.

Observation Haki

Mousse possesses exceptionally advanced Observation Haki, compensating for his initially poor physical talent.

• Displays Haki and vitality as numerical data 62 64.
• Distinguishes vitality from actual combat strength after observing fighters with misleading size-based values 64.
• Perceives structural weaknesses, allowing him to cut marble and metal with a small knife without Armament Haki 68.
• Uses refined self-perception to regulate training volume and avoid injury 84.
• Uses self-hypnosis triggers to suppress abnormal mental states and resist charm-type abilities 325.

Big Head

Big Head is Mousse's unique Poneglyph-based Homie, originally created from a Road Poneglyph with Linlin's Soul-Soul Fruit assistance 36 40.

• Can fly, alter shape, assimilate rock, and gain memories and strength from assimilated material 36.
• Can transform into a Rock Giant, though that form cannot fly and exposes Mousse to danger due to its size 38.
• Can become an almost indestructible scroll with extreme cutting power 39 40.
• Has a mass exceeding 300 tons and can be used as a devastating blunt weapon 40 158.
• Reached speeds exceeding 700 km/h through Mousse's development, then surpassed the speed of sound after his Ohara studies 152 158.
• Its combination of properties cannot be replicated, as it depends on the unique interaction of a Poneglyph, Mousse's fruit, Linlin's fruit, and Mousse's unusually strong soul 40.

Marksmanship and Mobility

Mousse trains in firearms and mobility techniques to offset his physical limitations.

• Uses compact, concealable handguns of his own design 144.
• Demonstrates precise marksmanship against small targets 144.
• Uses Seastone bullets to neutralize Devil Fruit defenses, including Capone Bege's Castle-Castle Fruit 270.
• Masters Soru and Geppo despite a comparatively low Power Level for Rokushiki users 292.
• Developed a battle suit with high defense, flexible flight, and near-limitless flight endurance 289.
• Retains uniquely implantable electric abilities, granting him extreme speed 291.

Scientific Research

Mousse is a scientist whose research focuses on Devil Fruits, Haki, genetics, martial arts, and technology.

• Investigates Charlotte Linlin's gigantification, durability, and abnormal strength through genetic comparison 4.
• Determines that Devil Fruit enhancement varies according to the fruit, the user's soul strength, physique, and degree of development 89 90.
• Concludes that learning and wisdom can improve Devil Fruit development for certain users 90.
• Develops safer methods to stimulate physical development through Haki after analyzing the Sea King Divine Skill 216 217.
• Researches Mink Tribe transformations, creating suppression potions and moonlight flares for safer on-demand activation 266.
• Invents a gyroscope for Grand Line navigation and develops the Devil Radar for Devil Fruit detection 94 291.

Equipment / Weapons / Items

• Big Head — Poneglyph-based Homie and Mousse's primary weapon, transport, and defensive asset 40 158.
• Compact handguns — Custom concealed firearms designed around his physical limitations and marksmanship 144.
• Seastone bullets — Used to disable Devil Fruit users such as Capone Bege 270.
• Battle suit — Provides high defense and highly efficient flight 289.
• Book Wings — A backpack transformed into wings and controlled through the Book-Book Fruit 193.
• Gyroscope watch — A miniaturized navigation, plotting, and locating device 230.
• Devil Radar — A detection device improved for greater range and portability 291.

Relationships

• Charlotte Linlin — Mother; favors Mousse unusually strongly and supports his research, though he remains wary of her instability 1 4 36.
• Charlotte Perospero — Eldest brother and early protector; gives Mousse the Book-Book Fruit and recognizes his scientific potential 1 3.
• Charlotte Katakuri — Elder brother, protector, and trusted strategic partner; Katakuri supports Mousse's plans while respecting his secrets 4 23 330.
• Nico Robin — Friend and student during Mousse's stay in Ohara; he recognizes her potential and decides to train her Devil Fruit abilities 142 145.
• Charlotte Custard — Younger sister and frequent collaborator; Mousse gives her the Copy-Copy Fruit and helps her develop its transformation potential 64 260 261.
• Charlotte Mont-d'Or — Brother whose military ambitions Mousse supports through advice, modern firearms, and Castle-Castle Fruit development 260 271.
• Cat Viper and Dogstorm — Mink leaders who trust Mousse after he researches safer Full Moon transformations; they provide him Life Cards 266.
• Bartholomew Kuma — Revolutionary Army elder whom Mousse meets after preserving Sabo in the Book World 308.
• Vinsmoke Reiju — Former hostage sent by Judge; Mousse removes her shackles and retains her as a subordinate 348.

Story Role / Major Arcs

Book-Book Fruit and Early Research

Mousse receives the Book-Book Fruit, demonstrates its instant-learning potential, and begins pursuing research into Linlin's genes, gigantification, and abnormal physical strength 1 3 4.

Strengthening the Charlotte Family

He advises Katakuri, Oven, Daifuku, Cracker, Brulee, and other family members on Haki, Devil Fruit development, combat techniques, and strategic growth. He also seeks the King's Fist to increase the family's combat potential 22 23 90.

Big Head and Poneglyph Research

Mousse creates Big Head from a Road Poneglyph, discovers its extraordinary transformations, and attempts to use the Book-Book Fruit to investigate Poneglyph secrets 36 38 39 40.

Dressrosa and Ohara

While visiting Dressrosa, Mousse's Observation Haki develops into a data-driven ability. He later travels to Ohara to read its library, meets Nico Robin, and greatly advances both his mental strength and Big Head's performance 62 64 142 158.

Flower Kingdom and Martial Arts Research

Mousse investigates the Flower Kingdom's conditions, analyzes the Sea King Divine Skill, refines its dangerous techniques into safer methods, and studies the nation's lost martial traditions 196 216 217.

Wano and Devil Fruit Distribution

After obtaining Devil Fruits in Wano, Mousse distributes them among his siblings according to their talents. He gives the Copy-Copy Fruit to Custard, the Brush-Brush Fruit to Brulee, and later acquires the Castle-Castle Fruit for Mont-d'Or 260 261 270 271.

Awakening and Expansion

Mousse awakens the Book-Book Fruit, strips powers from members of the Donquixote Family, and expands his influence through captured Devil Fruits, subordinate recruitment, and intervention against former Shichibukai 330 348.

Notable Quotes

“Mama, controlling books is not a useless ability. What I control isn't just the physical books, but also the content recorded within them!” 3

“If I can get their blood samples, I can compare them with yours and figure out whether your gigantification came from a bloodline mutation or from external factors during your infancy.” 4

“Since I possess the power to change the world, why not transform this world into the shape I like?” 240