So'unga

So'unga was a sword Inuyasha's father once owned, one of the Three Swords of World Conquest, Tessaiga (The Sword of the World of Man), Tensaiga (The Healing Sword of Heaven) and So'unga (The Sword of Destruction from Hell). In the third Inuyasha Movie, the sword arrives in Kagome's time and the centuries' old seal is broken, unleashing the dark powers caused by an evil spirit embedded in the sword, and it takes over other's minds, causing them to ruthlessly destroy other things. So'unga also has the power to bring back people and youkai from the underworld. However, both the powers of Tessaiga and Tensaiga must be combined to seal So'unga back into the underworld forever.