The Souba (双刃, Souba?) is a weapon in Final Fantasy VII: Advent Children used by Kadaj, leader of the Remnants of Sephiroth, as his primary weapon. The Souba is a katana with two reinforced parallel blades, set a small distance apart from each other. The design's intent is to trap an opponent's blade between them and disarm them. Despite it being much smaller than the Fusion Swords, Kadaj is able to battle Cloud with the Souba with no apparent handicap, taking advantage of the dual blades' wider striking range to more easily deflect Cloud's attacks.
The blade is lost in the ruins of Midgar during his final battle with Cloud, but after Kadaj reforms into Sephiroth and is subsequently defeated, it regenerates with him. Following his death in Aerith's Great Gospel, both Kadaj and the sword vanish into the Lifestream.
- The Souba's two blades could match the blade length of Sephiroth's Masamune, if lined up. This could be a reference to Kadaj being a remnant of Sephiroth.
- Some of the Souba's replicas can be split into two katana, but this feature has not been officially confirmed.