Yin and Yang swords

Yin and Yang swords wich are sed to have been the Sage of the Six Paths swords and also wer intended to be passt down to the Senju Clan Ancestor  and the Uchiha Clan Ancestorare curently in the posetion of Saizō Hidemaru how he ataind those swords is unknown

Powers
who ever is in the possession of the swords can utilize the Yin chakra, that comes from the spiritual energy, and the Yang chakra, that comes from the physical energy, also it grants the user the ability to utilize the Izanagi power wich maikes the wielder of the Yin Yang swords practicly invicebale.

Drawbacks
In return to grait power if the wielder dose not poses nether the uchiha or senju blood the wielders body cannot completely adjust to it, hence costing them more chakra than it would an for a senju or uchiha and in consistent use it shortens your lifespan.