Sō’unga (叢雲牙, "Amassing Cloud Fang") was a demon sword. It was the opposite of Sesshōmaru's inherited sword, the Tenseiga, "The Sword of Life or Heaven," as Sō'unga was 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 were the only swords that were capable of defeating Sō’unga, which was stronger than either of the two swords alone.