Name: Jin
Age: 20
Profession: Ronin
Weapon(s): Katana, Wakizashi
Fighting style(s): Mujushin Kenjutsu, Jujutsu
Quote: "Cutting down a man who's done nothing wrong; is that what you spent all that time honing your skills for? In my opinion, you're worthless."
Appears in: All episodes
Final status: Alive

Jin (仁) spent the vast majority of his life training in kenjutsu dojos. Unlike Mugen, it is legal for him to carry a daisho (two matching swords: a katana and a wakizashi), as he is of the samurai class. His swords have a lightning and twin-eyed design on the tsuba. He wears traditional hakama and gi in indigo blue patterned with a white diamond kamon made up of four small white diamonds. His kamon closely resembles that of the great Takeda Clan, leading to speculation that his family origins may be of nobility.^[5] He also sports a Buddhist rosary and a pair of anachronistic wire-rimmed glasses (which he does not actually need), the latter of which is probably the single most distinctive aspect of his appearance and the one everybody remembers.

When he was 18, he was to be assassinated in his sleep by his sensei, Mariya Enshirou, at Kariya Kagetoki's insistence. Jin killed Mariya in self-defense, to his horror. He fled the dojo, becoming a ronin. His death is sought by many, including former classmates and not limited to fame-seekers. Mujushin was a real sword-fighting dojo, and Mariya Enshirou is known to have been the third master — although the circumstances of his death are unclear.^[6] The esoteric teachings of Mujushin become vitally important in the series finale. Jin is highly devoted to upholding Bushido and is in fact named after jin (benevolence), one of the seven samurai virtues.^[7]

Jin is usually taciturn and unusually collected. He is an extremely skilled swordsman, using swift, refined, orthodox moves of the Mujushin Kenjutsu discipline, making him the perfect foil for Mugen. Like Mugen, he needs not rely solely on his sword. In one scene, he falls back on Jujutsu techniques, disarming and incapacitating at least six armed samurai before getting his daisho back. His dedication to the sword is so intense that he seems to lack abilities in other areas like holding his liquor, playing the shamisen, cooking eel and fishing. As a testament to his intelligence and unwillingness to readily trust others, he usually is the first to suspect when someone is not who they seem. He is also a formidable player when it comes to board games, especially shogi, and takes his time to think about his moves and doesn't fret to put his life on the line against his opponent.

In the last episode, he confesses to both Fuu and Kariya that he has spent his entire life with no devotion to anyone. He lived only for his sword and no master; saying that the lords of that time have no sense of honor, only caring about self-preservation. But he seems to change during his travels with Fuu and Mugen, saying that they are his "first friends."

His seiyū is Ginpei Sato. His dub actor in the U.S. version is Kirk Thornton.