Though his body is a clone, he is the man himself, possessing memories up until the moment of his death. He was created as a clone by scientists under Mitsunari Tokugawa, using somatic cells taken from his remains. When his body was first completed, it was literally a vessel without a soul, but Mitsunari's sister, the medium Sabuko Tokugawa, summoned his true soul from the underworld and breathed it into him. At that moment, his previously unblemished body was suddenly covered in scars, and his features, such as his eyebrows, shifted, shocking the scientists. He has a transcendent personality and high adaptability; he quickly accepted the explanation of his resurrection as a clone and acclimated to modern life within days. However, he is still overwhelmed by the sights of modern Tokyo, with its skyscrapers, cars, trains, and flamboyantly dressed people. He also seems uncomfortable with cars; whenever he rode in one, he would grumble for the driver to go a bit slower. While he undeniably has a violent, battle-crazed side, he is also quite frank and possesses a sense of humor. Yet, he is well-versed in etiquette and shows respect to grapplers who challenge him with their refined martial arts, even if their skill is inferior to his. After defeating Retsu Kaioh, he praised him, stating he had fallen for Retsu's skill, effort, and pride as a martial artist. Even toward Goki Shibukawa, who launched a surprise attack, he refrained from retaliating directly, settling for an "air cut." He also showed concern for Pickle after defeating him, later forming a bond close to friendship. When his battle lust is triggered, he radiates a demonic fighting spirit. On the other hand, he worries about having no place in the modern world, including its scientific advancements, and seems aware that, in Baki's words, he cannot "cut his way up" in this era. He shares these values regarding martial arts and warfare with Izo Motobe, and Yujiro noted that Motobe was vindicated by Musashi's appearance. Motobe, feeling a sense of responsibility as one who shares these values, moved to protect the other grapplers, Yujiro, and even Musashi himself. Motobe, understanding Musashi's loneliness, confronted him with the martial arts of old and, though Musashi held back significantly, Motobe emerged victorious. Musashi thanked him, saying, "Thank you. Even so, you have won." He also holds an inner respect for those he recognizes as strong in both mind and body, even if he doesn't say it to their faces. This strength includes spirit; he acknowledged Motobe and confessed to falling for Retsu Kaioh. Even toward Doppo and Baki, whom he taunted during their first meeting, he later evaluated them highly in conversation with Tokugawa. Furthermore, he often takes damage on purpose to experience new things and reacts to fighting spirit; despite his worldly desires, as a man who lived for the way of the sword, his interest in duels and self-refinement is immense, going beyond mere indiscriminate bloodlust.

The legendary swordsman of the early Edo period, Shinmen Musashi-no-Kami Fujiwara no Harunobu. Known to all as—Miyamoto Musashi. A master of the Niten Ichi-ryu style she founded, wielding both the long and short swords. ...Or so it should be, but her circumstances seem different from the Musashi recorded in correct history. She is a natural, relaxed person who doesn't put on airs. She has little interest in victory or fame, is sloppy with alcohol, has no resistance to money, and gets giddy over free drinks, treats, or free lodging. Yet, those who fought and lost to her all left the same testimony. In correct history, she was born in Mimasaka Province (modern-day Ohara, Mimasaka City, Okayama Prefecture) in Tensho 12 (1584). Her father was a martial arts instructor serving the Shinmen family, lords of Takeyama Castle, and was granted the Shinmen name, calling himself Shinmen Munisai. Munisai established a dojo for jutte techniques in Miyamoto Village, Yoshino District, and because Musashi called this place home, she later took the surname Miyamoto. As she grew, she made a name for herself as a tactician. After serving in the Shimabara Rebellion, she was taken in as a guest of Hosokawa Tadatoshi. While training successors, she wrote The Book of Five Rings and passed away in Shoho 2 (1645). She left behind many anecdotes throughout her life, but her battles during her 20s are particularly famous, with matches like the duel at Ganryu Island still recognized as entertainment staples today. While famous as a swordmaster, she was also gifted in the arts; three of her ink wash paintings—Cormorant, Shrike on a Withered Branch, and Wild Geese among Red Plum Blossoms—remain today as masterpieces designated as Important Cultural Properties. However, the details of most of her battles during those ten years are shrouded in mystery and heavily suspected to be fiction. For example, the famous duel with the Yoshioka clan is now known to be largely fictional; while it was said she wiped them out, the dojo actually closed much later following a different incident, and the family succeeded in the dyeing business. The life of Musashi known today is based on her own Book of Five Rings, the Kokura Monument erected by her adopted son Iori, and the Nitenki compiled by disciples, which is thought to be heavily embellished. Other historical materials exist, but they vary wildly, containing anecdotes found only in specific texts, making it difficult to discern the truth. Furthermore, the modern image of Musashi is heavily influenced by Eiji Yoshikawa's novel, including her relationships with Otsu, Matahachi Hon'iden, and Takuan Soho. Unlike the Wielder of the Second Magic, she cannot travel between worlds freely and usually jumps into distortions in space-time that happen to open.