Ryuuzan Hayashi

Ryuuzan is brilliant, obsessive and unwilling to accept the limits imposed by mortality. His love for Fuyou Hayashi motivates much of his research, but that affection becomes entangled with a determination to overcome death through technology.

His approach to machines differs sharply from that of Gengai Hiraga. Gengai describes Hayashi's creations as intricate and beautiful, contrasting them with his own rougher machines. Ryuuzan treats artificial intelligence as a means of preserving and reproducing human existence rather than merely building useful tools.

Ryuuzan has no supernatural powers, but he is one of Edo's most accomplished roboticists. He develops sophisticated household robots capable of independent movement, communication and complex behavior.

His greatest achievement is the Fuyou Project, which attempts to extract, store and reproduce human personality data inside artificial bodies. His technology ultimately makes androids such as Tama possible.

Ryuuzan also possesses sufficient expertise to work on the boundary between human consciousness and artificial intelligence, placing his research well beyond ordinary consumer robotics.

Ryuuzan's research provides the foundation of the Fuyou Arc. His sickly daughter Fuyou becomes the focus of experiments intended to preserve her personality data, while his laboratory produces increasingly sophisticated machines.

After Fuyou's death, Ryuuzan becomes consumed by the idea of restoring her through robotics. He ultimately transfers his own consciousness into the robot No. 502 and engineers the circumstances surrounding his apparent death.

Tama's arrival at the Yorozuya draws Sakata Gintoki, Shimura Shinpachi and Kagura into the consequences of his research. Ryuuzan's attempt to use Tama and the Fuyou Project to reproduce his daughter ultimately brings him into direct conflict with the Yorozuya.

Fuyou Hayashi is Ryuuzan's daughter and the central motivation behind the Fuyou Project. His inability to accept losing her drives his most extreme experiments.

Tama is Ryuuzan's creation and contains personality data derived from Fuyou Hayashi.

Gengai Hiraga is a fellow inventor whose philosophy of machinery contrasts with Ryuuzan's refined approach.

Professor Meguro is associated with Ryuuzan's research facility and the robotics work surrounding the Fuyou Project.