Z Sword

The Z Sword was lodged grip-side-up in a stone plateau on the Sacred World of the Kais for roughly 75 million years. According to legend, the warrior who pulled it free would gain access to phenomenal power. Every Supreme Kai who attempted to remove it over the millennia failed, adding to its mystique.

The truth behind the Z Sword was considerably less glamorous than the legend suggested. Approximately 75 million years before the main story, a short-tempered God of Destruction, Beerus, sealed Old Kai inside the blade during a disagreement at one of the periodic coordination meetings between Supreme Kais and Gods of Destruction. The actual reason for the argument was so trivial that Old Kai himself forgot what it was about. Over time, the truth about the sword became lost, replaced by the more inspiring legend of hidden power.

The blade itself resembles a hand-and-a-half sword with a wide cutting edge. Despite its legendary status, the sword is not particularly sturdy and possesses no special enchantments. Its extreme weight was the result of containing Old Kai within it, not any magical property of the metal. The sword was, in essence, nothing more than an elaborate prison.

During the Buu Saga, Supreme Kai Shin brought the injured Gohan to the Sacred World of the Kais to heal and, more importantly, to attempt pulling the Z Sword from its resting place. Despite the skepticism of Kibito, who constantly reminded Gohan that he was merely a mortal, Gohan succeeded in freeing the blade after transforming into a Super Saiyan.

Gohan trained with the Z Sword to build his strength, and while the training produced noticeable improvements due to the blade's crushing weight, Gohan felt that the sword itself was nothing special beyond being heavy. When Goku visited from Other World, they decided to test the sword's cutting limits by having Shin materialize a cube of Katchin, the densest material in the universe. The Z Sword shattered against the Katchin block, but this apparent disaster turned into a blessing: the breaking of the blade released Old Kai, who then used his ability to unlock Gohan's dormant potential, transforming him into one of the strongest fighters in existence.

In Future Trunks' timeline, the Z Sword met a different fate. Future Trunks trained with it successfully and grew stronger, but during his battle against Future Dabura, the demon spat on the blade and petrified it. When the stone sword broke, it killed Future Old Kai, who was still sealed inside. This tragic outcome meant Future Trunks never received the potential unlock that his main-timeline counterpart gained from Old Kai's release.