Jin Uzuki is Shion Uzuki's calm, composed, and older brother. Jin runs an antique bookstore on the outskirts of Second Miltia's capital. He formerly served as a captain in the Galaxy Federation's Special Forces Intelligence Division, but left the military during the Miltian Conflict. Jin is also an expert swordsman along with his rival, Margulis. Jin is unsure how to relate to his younger sister due to past events, and their relationship is often terse and uncomfortable.

In addition to being a master swordsman, Jin is an Ether specialist. He is always seen carrying around a katana within Episode II, whether or not it is an ancient weapon or recently forged weapon or if it belonged to his grandfather is not known, although the various katanas he wields in Episode III and having the ability to purchase them shows that some weapons were recently forged. He is essentially a samurai but this may be a personal feature, he appears to be Buddhist and has some traits from Bushido but this may a whimsical hobby, this can be seen with his rival Margulis also trained under the same sensei but uses a vastly different weapon and fighting style.

Jin lacks Margulis's strength but appears to be slightly faster and much smarter. Notably Jin's style of fighting is calm and controlled while Margulis relies on his rage and aggression and often his arrogance.

(source: Wikipedia)