Blessed rain

You conjure up a heavy rain cloud that is glowing with radiant light. The cloud grows to a diameter of 500 ft. When summoned, the raincloud starts to rain down holy water for the entire spell duration. Every round at the beginning of your turn. Any undead, fiend, or aberration under the rain cloud must make a constitution saving throw or take 2d6 radiant damage, half damage on a success. This damage cant be healed until the creature takes a long rest. Any creature that isn't an undead, fiend, or aberration under the rain cloud can't be charmed, frightened, possessed or have their hit point maximum reduced for the duration.