It's called the First Tsurugi:
The First Tsurugi consists of one main blade (Vigilante), one hollow blade that serves as the front edge (Vendetta), two identical (but asymmetrically opposite) blades that form the back (Merciless and Avenger), and two identical (also asymmetrically opposite) smaller blades that attach to the sides (Ascalon and Sidewinder). The swords of the First Tsurugi in its disassembled state are usually stored in racks inside the special compartments (three racks per compartment) on both sides of Cloud's motorcycle, the Fenrir. The First Tsurugi, much like the Buster Sword, is primarily a crushing weapon.