Celestial nod

The radiant energy from mount celestia drifts through you. You nod at a creature that you can see. A radiant shield surrounds the target, protecting them from dangerous attacks. The target gets a +5 bonus to armour class and the next time they get hit by an attack half of the damage dealt (rounded down) is inflicted back onto the attacker. Once the shield is attacked, it disappears and anyone within 10ft of it must make a dexterity saving throw or take 2d10 radiant dmage.