Aura of Protection I

When an ally within 5 meters of you is about to take damage from any source, you may expend 2 Bonus Actions to Activate Protective Aura. You may also activate the spell on your turn using 1 Bonus Action. A blue and white prismatic aura spreads over a 5 meter radius emanating from you. Any time, including the activation, an ally takes damage inside the aura, they reduce damage taken by 1. The aura lasts for 10 rounds, until you decide to end it (Free Action on your turn) or it is replaced by another aura.