|Significant other||Takezo Kensei|
Takezo Kensei gives his life for a princess, according to legend.
Hiro recalls his father's stories, including one about Kensei and the Dragon. He remembers that the dragon demanded the princess, Kensei's love. Kensei refused and used his sword to cut out his own heart.
The documentary Sword Saint records how Kensei and the princess fell madly in love. When she saw that Whitebeard threatened Japan's security, she asked her love to protect the country. He did so, and kept his promise. Takezo and the princess eventually got married, but the ceremony was interrupted by the Dragon of Kiso Mountain, who came looking for Kensei's love. To protect his beloved, Kensei cut out his own heart and gave it to the Dragon. Some believe she mourned the death of her love for the rest of her life, while others believe Kensei was brought back to life and the two escaped with the Dragon. However, exactly what happened after that remains a mystery, as does the exact identity of the princess. Some historians believe she is the Otsu villager Yaeko, daughter of the swordsmith, and the creator of the Kensei tapestries.
- Hiro tells Charlie the story of Kensei and the Dragon. Part of the story includes the dragon demanding payment from Kensei: the life of the princess's whom Kensei loved. (Chapter 23)
- Hiro compares Kaito's love for the late Satsu to Kensei's love. But since Satsu is unfamiliar to Hiro, he asks, "Who was his princess?" (Chapter 44)
A tapestry in the Museum of Natural History...
...shows Kensei defending his princess.
Kensei will not allow the dragon to take his love.
...and her witness of his suicide on the selfsame day.