The Dragon Blade is made from the tooh of Damia, and has been forged by an unknown person to now serve as a weapon. The dragon blade has three main functions:

1. The Dragon Blade enables the user to cut and absorb their opponents' chakra
2. The sword will return to its current owner (which is decided via blood ritual and ownership transfers either upon death or willingful forfeit of the weapon) upon the owner holding out their hand and mentally demanding it to return.
3. The dragon blade when wielded can enhance jutsu's, or perform jutsu's that the user could not normally perform because they were too weak.

Note that wielding the dragon blade slowly drains it's user of chakra.