Pickle is a prehistoric human who appears in the Baki Hanma story as one of its most formidable and primal figures. He is a primitive man who lived during the age of the dinosaurs, in the Jurassic or Cretaceous period, where he existed as the dominant predator of his ecosystem. Without weapons of any kind, he hunted, killed, and ate enormous dinosaurs, including Tyrannosaurus rex, using only his physical body. He was discovered in modern times perfectly preserved inside a thick saline rock formation in the United States, which is the origin of his name, because he was effectively pickled in salt. He had been frozen for hundreds of millions of years when a catastrophic asteroid impact caused the planet to cool dramatically, and he was later revived by scientists. Upon awakening, he overpowered military battalions and advanced equipment sent to capture him before being transferred to Japan.

Physically, Pickle stands over eight feet tall and possesses an extraordinarily massive, muscular build developed through a lifetime of battling dinosaurs. His appearance is distinctly nonhuman by modern standards, with exaggerated canine teeth, claw-like nails, extremely thick neck muscles, and long, powerful limbs. His body is so dense and durable that he can withstand pistol fire at point blank range without being penetrated, survive collisions with vehicles, and endure blows that would devastate ordinary fighters.

In terms of personality, Pickle is best described as savage but naive. He does not understand modern speech, culture, or social conventions, and communicates primarily through growls, roars, facial expressions, and physical actions. His mindset is shaped entirely by the instincts of a hunter and survivor. He interprets the modern world through the logic of his prehistoric life, viewing other fighters as potential prey or threats rather than as opponents in a sporting contest. He does not fight for honor, fame, or personal pride in the way other characters do; he fights because attacking and overpowering threats is his natural way of engaging with the world. At the same time, he is not simply a mindless beast. He demonstrates remarkable intelligence and learning ability, such as copying fighting techniques he has only seen once, understanding when he is being tested, and adapting his behavior to unfamiliar situations. He shows respect for opponents who match him in strength, displays curiosity about his new surroundings, and is capable of forming bonds of a sort with certain people.

Pickle's motivations are rooted in basic biological needs. He seeks food, and his preferred meal is the flesh of strong opponents who attack him. He holds to a consistent personal rule of only consuming those who come at him, and he treats combat itself as an extension of hunting. Beyond survival, he is driven by an instinct to prove his dominance against powerful beings, and he takes pride in his status as a mighty predator. He shows raw emotional responses to his victories, such as celebrating by raising his fists in a dance, mourning the loss of worthy adversaries, and even offering a form of respect to opponents whose strength impressed him by refusing to eat them. His primal instincts also sometimes override modern social boundaries, leading him to act on impulses without awareness of contemporary norms of behavior.

In the story, Pickle serves as the central figure of the Pickle Wars saga, in which the strongest fighters of the modern era are drawn to test themselves against him. One by one, he defeats notable martial artists in brutal encounters, including Retsu Kaioh, whose body he injures and partially consumes, and Katsumi Orochi, whose right arm he takes in their fight. He engages in a strength contest with Yujiro Hanma, the strongest being in the world, forcing even Yujiro to resort to technique rather than sheer force. He also fights Jack Hammer twice, overpowering him and defeating his bite with an even more powerful bite of his own. His most significant confrontation is his battle with Baki Hanma, the protagonist. In that fight, Baki initially uses skill and technique to overwhelm Pickle, but Pickle adapts, unlocks a latent ability to learn, and ultimately defeats Baki in a direct exchange of blows. Although the outcome is interpreted in different ways by observers, the fight proves to be a turning point for Pickle, as it convinces him that he can survive and even belong in the modern world.

His key relationships are defined through combat. He respects Yujiro Hanma as a true force of nature and responds to his overwhelming presence. His bond with Baki Hanma becomes the closest thing he has to friendship, as the two connect through the language of fighting and part with mutual acknowledgment. He forms an uncharacteristically protective attachment to Biscuit Oliva in one of his quieter moments, showing that beneath his savage exterior he is capable of gentleness, loyalty, and even compassion. He also has an ongoing association with the scientists and military handlers who revived him, particularly the researcher who studies him and the officer who escorts him to Japan, though he never fully understands or submits to their authority.

Over the course of his appearances, Pickle develops from a confused, purely instinct-driven wild man into a more adaptable presence. He learns from every fight, gradually acquiring techniques and strategies from his opponents, and he begins to recognize the value of restraint and compromise when his original hunting rules prove impractical. Later in the story, he is shown living on his own in the sewers of Tokyo, surviving by hunting creatures released into the city rather than attacking people, which demonstrates his capacity to adjust his behavior to new conditions. Despite this growth, he remains fundamentally a creature of instinct, bound to his nature as a hunter and fighter, and uncertain in his place in a world that is utterly foreign to him.

Pickle's notable abilities are almost entirely physical but are far beyond the limits of any normal human. He possesses immense raw strength, allowing him to lift enormous weights, smash vehicles, break metal restraints, and overpower some of the most powerful fighters in the series. His durability is equally extreme, with muscles and bones so dense that they resist bullets, blows, and even cutting attacks that can slice through armored protection. His bite force is among the strongest in the story, capable of tearing through dinosaur hides and metal, and strong enough to overwhelm the dedicated biting style of Jack Hammer. Despite his size, he is exceptionally fast and agile, able to evade attacks at speeds that appear almost like teleportation and to hunt creatures that strike with lightning-quick reflexes. His senses are heightened to animal levels, including extremely sharp vision and a keen sense of smell. He employs a signature hunting charge in which he drops to all fours and launches himself at his target like a projectile, a technique he once used to bring down dinosaurs. When truly enraged or faced with a serious threat, he enters a heightened combat state sometimes called his Final Form, in which his physical attributes increase dramatically, his joints twist at unnatural angles, and old scars from his survival of a Tyrannosaurus attack become visible on his body. He also proves able to copy and use techniques he witnesses, including forms of aikido and martial arts, making his adaptability as dangerous as his brute force.