- A demon sword. It is the opposite of Youko's signature sword, the Tenseiga, "The Sword of Life or Heaven," as Sō'unga is considered "The Sword of Death or Hell." Sō’unga, "The Sword of Hell or of World Conquest," could summon 100 dead souls in one swing. The combined powers of the Tessaiga and the Tenseiga are the only swords that are capable of defeating Sō’unga, which is stronger than either of the two swords alone.
Prison Dragon Blast (獄龍破, Gokuryūha): Sō’unga's most powerful attack; it possesses more destructive power than the Tessaiga's Backlash Wave. Sō’unga unleashes a large, violent, and powerful purple/black tornado that annihilates everything that is caught in its path. Youko described this as being the attack of a dragon from Hell. Its strength is so great when used at maximum potential that it could easily bowl-over the Backlash Wave. However, if both Tessaiga and Tenseiga are close by, the strength of the Dragon Twister is greatly diminished.
Reanimation: Unlike other weapons which includes demon swords as well, So'unga's slain victims don't simply die but their corpses are reanimated as soulless undead that unless specially commanded will mindlessly attack the living in their vicinity. When Sō’unga is in control of a "lesser" being (one with chakra reserves lower than the wielder's), it could bring the corpses of the dead or the recently deceased back to life and take control of them, or even semi-revitalize one's appearance and give it free will. When it does this, either he plants himself into a grave and call upon their spirit to inhabit their former bodies or have its blade release a blood red-like liquid that animates them. A power that's even able to counteract the anti-undead aspects belonged to those of the Tenseiga. Aforementioned mindless corpses are filled with deadly, liquefied miasma which, when at Sō’unga's full power, enable said specters to restore themselves from most kinds of damage. To counteract this, Hakudoshi seems to impose his own will upon the revitalized corpses.
Possession: It was said that if a weaker human were to grab hold of So'unga, then they would be under its control, and if a strong human were to take the So'unga, then it would attempt to sway them to the best of its abilities to do its bidding. This was shown when Kanna was possessed by the So'unga when she was brought to life by it, and it was discovered that she was taken over due to a weaker state of mind alone. However, it is proven that if the possessed individual has enough mental strength and willpower then they can momentarily resist So'unga's control, as demonstrated by Kanna as well.
Self-Sustained Body: Out of desperation, Sō'unga could mold a physical body of armor, though it lacks a head. While it possesses no proper arm, its left one is a giant curved blade that is wielded effortlessly with precision and speed. This armor can be invoked by Hakudoshi, and when this is done by the will of So'unga's wielder, his head and right arm are fully exposed.
Black Spikes: Sō'unga could fire a shower of black spikes to impale its enemies much like Tessaiga's adamant barrage, though he seems to require continuously swinging his arm in the direction to fire the spikes, while Tessaiga's adamant barrage only needs one slash.
