Sword of Masters is the second unlockable sword, and can be unlocked by completing the "Master Key" achievement. Sword of Masters is a reference to the "Master Sword" from the Legend of Zelda series, and functions similarly to the default katana, but has the added function of firing a single energy blast when the player swings. The energy blast is functionally identical to a thrown weapon, and takes a few seconds to charge between blasts. The player can still attack normally while the energy blast is recharging.
Swords are the main weapons used by the player in Katana Zero. The player starts with a default Katana in the beginning of the game, but can unlock 5 others via achievements. The unlockable swords can be switched in and out in the Government Lab level, which is unlocked after beating the game.