War Sword

War Sword is a greatsword. It has a 10% chance of inflicting the Compromised debuff on targets when used by either Noctis or Gladio.

Source
War Swords can be purchased from Culless Munitions at Hammerhead, Galdin Quay, and the Prairie Outpost for 150 gil. It is used as a starter greatsword by both Gladio and Noct at the beginning of the game. It can be sold back to shops for 75 gil.