Heaven's Herald

This golden trumpet is never dulled by rust or dirt. As an action, a good-aligned creature can blow the trumpet, which emits a rousing battle song that can be heard up to 600 feet away. The creature blowing the trumpet can choose up to 12 allies within the area to receive the benefits of heaven's herald. An allied creature becomes immune to being frightened and makes all Wisdom saving throws with advantage. In addition, its hit point maximum increases by 2d10, and it gains the same number of hit points. These benefits last for 24 hours. Once used in this way, the herald cannot be used again until dawn. If a neutral-aligned creature attempts to use the trumpet, no sound emerges, and nothing happens. If an evil-aligned creature attempts to use the trumpet, the creature must succeed on a DC 15 Dexterity saving throw as a column of divine fire roars from the heavens to smite the user. A creature takes 8d6 radiant damage on a failed save, or half as much damage on a successful one.