Bear Cub

Biodata

Feature	Details
Name	Winter 4
Alias(es)	Bear Cub 4
Species/Race	Red panda, later altered into a panda-like Devil Fruit user 4 7 26
Gender	Male
Affiliation	Mercer's group; later works with Karasu and Crow Xiaoniu on Newspaper Agency affairs 328
Occupation/Role	Mercer's companion, younger brother, mount, scout, forge assistant, and combat partner
Status	Active; leaves with Karasu and Crow Xiaoniu to handle Newspaper Agency matters 328
First Appearance	Chapter 4 4

Power Progression

Stage / Realm / Level	Chapter	Notes
Munch-Munch Fruit user	7	Mercer feeds him the Munch-Munch Fruit, later referred to as the Gulp-Gulp Fruit. The fruit alters his body, diet, and species-related weaknesses.
Basic special breathing technique	10	Learns the foundations of Mercer's breathing method, improving control over his own body.
Overall Evaluation: E-	26	Can compress and refine ore into low-purity F-rank alloys, though his combat power is still considered secondary to his unusual appearance.
Creature and humanoid assimilation	31 32	Learns to manifest traits of consumed animals, become a Snow Chicken-like creature, and reshape himself into a Panda Man-like humanoid capable of speech.
Bald eagle flight	65	After consuming a bald eagle and training for six months, gains a flight-capable eagle form.
Unity of All Things; Observation Haki	161	Through repeated Fusion training with Mercer, comprehends Unity of All Things and awakens Observation Haki.
Strength Evaluation: C	193	Receives Flesh and Blood Essence from Mercer to improve his physical strength and potential.
Origin Magic: Personification	328	Uses Origin Magic to assume a sturdy human form with black-and-white hair.

Background

Mercer found Winter as a dying cub and pleaded with Kureha to save him. Kureha agreed only after Mercer accepted full responsibility for the cub's care. Mercer named him Winter, while “Bear Cub” became his everyday nickname. Kureha also helped raise him, despite initially resisting the role. 4 10

Winter grew quickly while living with Mercer and Kureha on Drum Island. He accompanied Mercer on hunts and herb-gathering trips, using his acute smell and hearing to locate food and medicinal plants while avoiding dangerous animals. 6 9

After Mercer acquired the princes' Devil Fruits, he chose to feed Winter the Munch-Munch Fruit. Winter's altered digestion allowed him to consume metal, weapons, ores, and living creatures, eventually developing the ability to reproduce their traits as part of his own body. 7 8 31

Mercer trained Winter to control these transformations, while Winter gradually learned human speech by altering his own bone structure. He ultimately chose to retain his usual panda form outside of training and combat, though Kureha later helped optimize the skeletal modifications needed for speech. 32 34

Appearance

Winter is a black-and-white, round-bodied panda-like creature with a deceptively large frame. At over two years old, he measured 1.5 meters long, 1.9 meters standing upright, and weighed 80 kilograms; he later grew to nearly three meters tall in his normal form. 10 162

• Black nose, black ears, black limbs, and dark circles around his eyes in humanoid form. 32
• Naturally nearsighted, but can manifest eagle eyes to gain long-distance vision. 4 140
• Possesses the panda species' pseudo-sixth finger. 32
• Can become a Panda Man-like humanoid with slightly curly black hair and a chubby build. 32
• His Origin Magic human form is a sturdy, honest-looking young man with black-and-white hair. 328

Personality

Winter is affectionate, food-motivated, and highly expressive. As a cub, he feigned pain to gain Mercer's protection, begged Kureha for sympathy when threatened with skipped meals, and eagerly shared food he considered delicious—even gold and burning charcoal. 4 8 10 31

He is loyal to Mercer and usually follows instructions immediately, whether serving as a mount, swallowing allies for transport, or assisting in training and combat. He also enjoys showing off new transformation forms and considers himself Mercer's younger brother. 115 129 170

Despite his confidence, Winter is self-aware about the gap between himself and exceptionally gifted companions such as Mercer and Eriyi. He considers himself “an ordinary Panda” by comparison, but continues training and seeking stronger forms. 154 161

Abilities & Skills

Gulp-Gulp Fruit

Winter's Devil Fruit allows him to devour and digest an extraordinary range of substances, including metal, weaponry, animals, buildings, and living people. 8 31 135

• Can chew steel and metal alloys as easily as food. 8 116
• Possesses a Dimensional Stomach, a dark internal storage space containing corrosive gas and limited air. 32
• Can hold swallowed people without immediately digesting them, often using the space for transport or confinement. 64 129 164
• Can retrieve stored objects, weapons, creatures, and people through his mouth. 32 115 170
• Devouring creatures with unusual spiritual abilities may carry risks; Mercer considers Fusion necessary before Winter consumes such targets. 150

Assimilation and Transformation

Winter can manifest properties of consumed objects and creatures onto his body, either as individual components or complete forms. 8 31

• Metal constructs — Forms blades, hammers, claw covers, full armor, and other weapons from consumed equipment. 8 25
• Alloy refinement — Compresses and refines consumed ore into alloy blocks for Mercer's forging projects. 26
• Animal forms — Has manifested Snow Chicken, bald eagle, saber-toothed tiger, Carnotaurus, Tyrannosaurus Rex, Megalodon, giant wolf, pterosaur, and other forms. 31 65 115 116 152
• Hybrid forms — Can combine animal traits into humanoid Mink-like transformations, such as a saber-toothed tiger warrior or dinosaur-headed humanoid. 115
• Structural assimilation — Can consume a building and recreate it as a functional transformed structure, including a laboratory. 135
• Limitation: Early transformations did not automatically provide every trait of a copied creature; his Snow Chicken form could not fly. 31

Fusion with Mercer

Winter can swallow Mercer and merge with him through a Pseudo-Fusion transformation. The resulting body combines Winter's Devil Fruit functions with Mercer's techniques and awareness. 32 34

• Mercer can assume primary control of the fused body, while Winter's consciousness becomes subordinate. 32
• Fusion enables forms such as Panda Man, bald eagle, and other assimilated creatures. 34 87
• Both partners benefit from Fusion training: Mercer deepens his understanding of Unity of Heaven and Man, while Winter improves his breathing and Haki comprehension. 34
• Maintaining Fusion consumes Winter's stamina; he ends the state when exhausted. 34

Breathing and Observation Haki

Winter learned the basics of Mercer's special breathing technique through imitation and sustained training. 10

• Improved breathing grants him greater bodily control, resilience, and agility despite his heavy build. 10 95
• Repeated Fusion cultivation leads him to comprehend Unity of All Things. 161
• Awakens Observation Haki, allowing him to sense threats and support Mercer's training. 161
• Uses eagle eyes alongside his sensory abilities for long-range reconnaissance. 140 170

Durability and Combat

Winter fights through a mixture of tough physiology, transformation-based weaponry, and overwhelming bite strength. His Strength Evaluation reaches C after receiving Flesh and Blood Essence. 154 193

• Can withstand severe impacts that would seriously injure ordinary humans. 154
• Uses body armor and transformed limb weapons against large beasts. 154 224
• Has used a Dodge Shell's shockwave, though its recoil leaves him in pain. 154
• Defeated and assimilated large prehistoric predators, including a Carnotaurus and Tyrannosaurus Rex. 115 116

Origin Magic: Personification

Winter learns Origin Magic through memory transfer and uses Personification to take on a human appearance. 328

• Assumes the form of a black-and-white-haired, sturdy young man. 328
• Retains his companionship with Karasu and Crow Xiaoniu after their transformation. 328

Equipment / Weapons / Items

• Baseball bat — Frequently stored inside his body and retrieved in humanoid or beastman forms. 87 115
• Dodge Shell — A shell weapon that releases a powerful shockwave but causes damaging recoil. 154
• Salt-Salt Fruit earring — Given to him by Mercer and fused to his ear; its specific effects are not described. 255

Relationships

• Mercer — Rescuer, caretaker, trainer, Fusion partner, and elder brother. Winter follows Mercer across the seas and is fiercely loyal to him. 4 32 129
• Kureha — Helped save and raise Winter; Mercer calls her Winter's “Mama,” much to her annoyance. 4 10
• Karasu — Fellow companion and frequent training partner. Winter later leaves with Karasu to manage Newspaper Agency business. 65 328
• Crow Xiaoniu — Companion who joins Winter and Karasu in handling Newspaper Agency affairs. 328
• Eriyi — Training companion whose extraordinary strength intimidates Winter, though he respects her deeply. 154
• Ulti — Sparring partner and fellow member of Mercer's group. 128 224
• Ace and Sabo — Initially attack Winter out of suspicion; Mercer introduces Winter as their younger brother. 129
• Bepo — A fellow bear-like companion whom Winter considers taking as a little brother; Bepo later addresses him as “Brother Bear.” 162 170

Story Role / Major Arcs

• Drum Island upbringing — Is rescued, raised by Mercer and Kureha, receives the Gulp-Gulp Fruit, and becomes Mercer's earliest animal companion. 4 7
• Forging development — Refines ores and alloys, allowing Mercer to establish a forge and create weapons. 25 26
• Fusion development — Learns humanoid transformation, human speech, and Fusion with Mercer, making him central to Mercer's travel and cultivation methods. 32 34
• Sky Island and New World journeys — Grows through giantization, aerial forms, combat training, and repeated hunts alongside Mercer. 84 87 152
• Little Garden exploration — Assimilates saber-toothed tiger and dinosaur traits while assisting Mercer, Yamato, and the others. 115 116
• Newspaper Agency separation — Takes human form through Origin Magic and departs with Karasu and Crow Xiaoniu to independently manage Agency operations. 328

Trivia

• “Winter” is a homophone-based name taken from Winter Island. 4
• Although commonly called Bear Cub, he began as a red panda cub. 4
• He prefers his original panda form in daily life, considering it more comfortable than his humanoid shape. 34
• His appetite is so large that Marine cooks are exhausted after meals shared with him and Mercer. 161