Dragon Invocation: Breath of Alidusax

You Invoke an essence of unknown that's hidden inside of you. You exhale a wave of destructive flames in a 90ft cone in front of you. Each creature within the cone must make a DEX save, on failure, the creature takes 5d10 +WIS modifier Unknown Damage and is inflicted with 1 stack of unknown. On a success, the creature takes half damage. If you use this miracle, while you are benefiting from "Placidusax's Rage", you can expend a bonus action to have all creatures who failed the saving throw take an extra 2d10 damage.