Battalion's Backup

Once per long rest you can blow into this magic bugle as a bonus action to empower both yourself and any allies within 10 ft. of you that can hear the sound of the instrument. While under the effects of the Battalion's Backup you and your allies takes half damage from bludgeoning, piercing, slashing, and fire damage as well as immunity to critical hits (turning them into normal hits) for 1 minute. If you have proficiency in the Horn instrument you can use this item a number of times equal to half your proficiency bonus (rounded down) per long rest.

Notes: Buff, Combat