The Six Lost Swords

The Six Lost Swords are swords from the time before ninshu was developed by the Sage of the Six Paths. The six swords each have a different power and have to bond with their user. When bonded with their wielder they give the wielder special powers they wouldn't have otherwise. Legend has it if all six swords were combined an all powerful sword would be created.

History
Before ninshu was created by the Sage of the Six Paths and people could not use chakra six different energies were spawned from the shinju. Most people feared and stayed away from these powers, until six brave warriors stepped forth. They tamed these powers and infused them with swords they had forged. These six warriors became powerful sages who led armies to war against one another. When Kaguya ate the shinju's fruit she defeated these six sages and the swords were lost forever. In the present day people say that the swords are hidden and guarded by powerful ancient seals that are little understood.