Ash Skin

You touch a willing creature. Until the spell ends, the target exudes an overwhelming heat from its ashy appearance, causing all attacks by creatures within 5 feet to be made at disadvantage.

Additionally, the target's body isn't as rigorous as it normally is, gaining vulnerability to Bludgeoning, Piercing and Slashing damage. Whenever the target takes damage they are vulnerable to, the heat within gets exposed, causing all creatures within 5 feet to take 1d4 fire damage.