Defending Sword

You create a sword of force that functions as mage's sword except as described here. The sword does not receive the additional +3 enhancement bonus a mage's sword receives, and deals 3d6 points of force damage. You cannot command the sword. Until the sword is triggered, it hovers in your space without interfering with your actions. While hovering in this way, the sword attempts to defend you from incoming attacks, granting you a +4 shield bonus to your AC. The first time a foe within close range damages you or forces you to attempt a saving throw that you fail, the sword is triggered and begins attacking that target as described in mage's sword for the duration of the spell. This ends the shield bonus. You cannot direct the sword to defend against a new target once it has begun to attack. If its target moves beyond the sword's range, the sword returns to you and hovers until the target is again within range. The sword's return does not restore the spell's shield bonus to AC.