Kensei sword/Season Two
For more about Kensei sword, see the main article.
Fleeing the burning Otsu in 1671, Yaeko encounters Takezo Kensei and takes the sword from him. Though Kensei and Hiro both impulsively claim ownership over the sword, Yaeko explains that it was her father who made the sword, so she is the rightful owner of it.
Hiro teleports Kensei to retrieve the fire scroll, and hands Kensei the sword. As the ninety ronin approach Kensei, he takes the sword to the ready. Later, Hiro uses the sword as a way to communicate with present-day Ando by sticking several scrolls hidden inside the sword's hilt. In the present, the sword is still broken. Ando reads the scrolls in the hilt to track Hiro's progress in the past.
Hiro is knocked out in his fight with Peter, and Adam claims the sword back as his own. Later, Adam uses the sword to fight against the Company's security guards. After Hiro teleports Adam to Aoyama Cemetery, Hiro reclaims the sword.
- Hiro tells Charlie that Kensei was a wild savage with great power, feared by all of Japan, until he found a sacred sword frozen in the snow. The sword focused Kensei's strength, let him control his power, and ultimately helped him become a great leader and hero. (Chapter 13)
- Hiro gives Charlie a reproduction of the legend of Kensei and the Dragon, which shows the muted red of Kensei's blood staining the sword. Hiro tells Charlie the story: Kensei finds his sacred sword and goes to the dragon so he can learn the secrets of the sword. Kensei uses the sword to fight his enemies and save his people. When the dragon demands payment, Kensei plunges the sword into his heart. (Chapter 23)