Airsault

The user creates a forcefield of air pressure that surrounds themselves. While the forcefield is active they gain a +2 bonus to their AC, and all ranged attacks have disadvantage as the air currents buffet incoming projectiles. Airsault has three charges, when the caster is hit by a melee attack, one of the charges is expended, and the attacker is hit in retribution. The attacker takes 3d6 force damage, and must make a Strength saving throw or be pushed backwards 15ft away from the caster. On a successful save the target still takes damage but is not pushed backwards. Once the final charge is used the spell ends.

At Higher Levels: When you cast this spell using a slot of 4th level or higher, the amount of charges before the spell ends increases by 1 for each slot level above 3rd.