Wall of Darkness

You summon a 30 foot long, 5 foot deep, 10 foot tall wall of darkened whisps of the souls of the damned, their bellows and skeletal forms grasping and stopping aoe spells.

When players have to roll a dexterity saving throw from behind the wall, the wall will absorb 2d6+5 points of damage from whatever spell/attack that was performed. The spell must be cast before the damage is known. (i.e. dragons breath of 77 damage.  If players roll dex and succeed, they take half damage, and reduce by 10)

At higher levels: At 4th level the spell blocks 3d6+5  points of damage, at 5th level 3d6+15 points of damage, and grants +2 to saving dex saving throws.  At 6th level: 3d6+30 and grants adv on dex saves. at higher levels, add 15