The Buster Sword is Cloud's initial weapon in Final Fantasy VII. In addition to being equippable by Cloud, it is also used by him in cutscenes and minigames. Due to this, it cannot be sold or thrown. The Buster Sword is a basic weapon with an Attack stat bonus of 18, and two linked Materia slots.
The Buster Sword also appears on the title screen, suspended over the ground surrounded by a black background. The icon for the Buster Sword also represents the "Weapon is Broken" handicap on the Battle Square handicap reels.
As the Buster Sword has a base Attack stat bonus of 18, meaning the base damage for physical attacks when the Buster Sword is equipped is in the following formula:
The Buster Sword is initially equipped by Cloud. It should be replaced upon acquiring a better weapon; Mythril Saber can be purchased at Kalm after leaving Midgar, though the Hardedge can be stolen earlier at the Shinra Bldg. As it cannot be sold, the Buster Sword should be left in the inventory after this point.
As the Buster Sword has two linked Materia slots, Cloud can link a Magic Materia early on with All, to take advantage of Cloud's high Magic stat. In the case of attack magic, such as Fire, Ice, and Lightning, this allows Cloud to deal heavy damage to a group of enemies with one spell cast. Similarly, it can be used with Restore to cure all party members at once. Later on, Cloud is a good beneficiary of the Elemental Materia, to link it with Fire, Ice, or Lightning and infuse Cloud's physical attacks with elemental damage and exploit an enemies' weakness to them.