TV-Series
Description
Jin Kusanagi is a significant character in the narrative, primarily known as the younger brother of Shoichi Kusanagi. His role is deeply tied to the traumatic past that drives much of the story's conflict.

Ten years before the main events, Jin was one of several children, including the protagonist Yusaku Fujiki, who were kidnapped for an incident known as the Hanoi Project, or the Lost Incident. During this time, the children were subjected to intense experiments involving dueling, which were used to create artificial intelligences called Ignis. The Ignis modeled after Jin's own data is named Lightning. The experience left Jin with severe psychological scars. According to Yusaku, Jin developed intense post-traumatic stress disorder from the ordeal. Prior to the kidnapping, he was a cheerful and outgoing child, but afterward, he became withdrawn, reserved, and closed off his heart from the world. He often appears with a dull, emotionless expression and has difficulty communicating, even with his devoted older brother.

Jin's condition is the primary motivation for both his brother and Yusaku. Shoichi gave up his sports ambitions to learn hacking, hoping to uncover the truth about the incident and find a way to help Jin. Similarly, Yusaku's quest for revenge against the Knights of Hanoi is intertwined with a desire to save Jin from the darkness that still holds him.

For much of the story, Jin is a silent, off-screen presence, mentioned frequently but only seen in brief flashbacks or at his hospital bedside where he is recovering. His situation becomes critical when his consciousness data is stolen by a being named Bohman, causing him to fall into a coma in the real world. This act forces his brother to take drastic action, confronting his ally Playmaker (Yusaku) in a duel under threat from Lightning, who holds Jin's consciousness hostage. In the virtual world of Link VRAINS, Jin is later used by Lightning as an unwilling proxy, forced to duel under the Ignis's control while in a trance-like state. His avatar in Link VRAINS has a different appearance, with shorter hair and a white cloak bearing Lightning's symbol.

A crucial development occurs when Shoichi uncovers the full truth about Jin's abduction, including the specific torment inflicted by Lightning to shatter his spirit. After his brother reveals this information, Jin begins to show signs of recovery, speaking more with his family and doctors. The story later establishes that Lightning had converted a part of Jin's own consciousness into an extra Life Point source, and with the removal of this manipulation, Jin lost his traumatic memories of the incident, allowing him to return to his original, more jovial personality. His key relationships are with his brother Shoichi, who acts as his unwavering protector, and with Yusaku, a fellow victim who sees Jin's salvation as part of his own mission. His most significant and antagonistic relationship is with Lightning, the Ignis born from his own data, who used Jin's trauma to learn how to inflict fear on others. Jin's notable abilities are not dueling-related in the traditional sense; his primary significance lies in being the origin of the powerful Ignis Lightning, and his unique consciousness data becomes a coveted object of power for the antagonist Bohman.