This page remains incomplete.
合体剣 [gattai ken] or 'union sword' in Japanese. This blade made itself known in Advent Children where Cloud Strife used it. The sword itself can be dismantled into 6 different smaller blades. This page has details on all of the parts as well as the completed Fusion Sword itself.
Fusion Sword 1st
Coming soon
aka: First Blade, Main Blade

Fusion Sword 2nd
Blade #2 of the Fusion Sword (合体剣2nd in Japanese) is actually hollow inside, and open on one edge to fit other parts of the Fusion Sword within it. The closed off edge is sharp and functions as a blade. The hollow inside doesn't seem to affect the sword's durability, as it's used to deal and receive blows just as any of the other parts of the sword.
The blade is sometimes known (or described) as the Hollow Blade.

Airborne Brigade

SR+
Type: Greatsword, Element: -, Growth: ?, Cost: ?
Attack: 6,529 (lv1), ? (lv120), ? (lv150), ? (lv180), ? (lv210), ? (lv240)
Defense: 5,663 (lv1), ? (lv120), ? (lv150), ? (lv180), ? (lv210), ? (lv240)
Obtain: (FF7AC event)
SR+
Type: Greatsword, Element: -, Growth: ?, Cost: ?
Attack: ? (lv1), ? (lv100), ? (lv125), ? (lv150), ? (lv175), ? (lv200)
Defense: ? (lv1), ? (lv100), ? (lv125), ? (lv150), ? (lv175), ? (lv200)
Obtain: (FF7AC event)
Fusion Sword 3rd & 4th

Fusion Sword 5th & 6th

Airborne Brigade

SR+
Type: Dagger, Element: -, Growth: ?, Cost: ?
Attack: 6,094 (lv1), 14,794 (lv120), ? (lv150), ? (lv180), 21,782 (lv210), ? (lv240)
Defense: 5,507 (lv1), 19,720 (lv120), ? (lv150), ? (lv180), 19,720 (lv210), ? (lv240)
Obtain: (FF7AC event)
Other: called Fusion Sword 4th in the game, despite being modeled after fusion swords 5 and 6
SR
Type: Dagger, Element: -, Growth: ?, Cost: ?
Attack: ? (lv1), ? (lv100), ? (lv125), ? (lv150), ? (lv175), ? (lv200)
Defense: ? (lv1), ? (lv100), ? (lv125), ? (lv150), ? (lv175), ? (lv200)
Obtain: (FF7AC event)
Assembling the Sword

Category: Equipment