AG's Boon of the Stormwarden

You have immunity to lightning and thunder damage. Additionally, if you would take more than 25 Lightning or Thunder damage from any single source, you become surrounded by a roiling storm. Enemies within 15ft of you are under the following effects.

• If they try to move out of the area they must make a strength saving throw against your spell save DC or 17. On a failed save, they take 20 points of lightning damage and are considered restrained until the end of your next turn.
• When a creature within the storm attempts to damage someone other than you, just before they do, you can use your reaction to blast them with concussive force. That creature has disadvantage on their attack rolls this turn, and if they were casting a spell, they must make a concentration check against your spell save DC or 17, interrupting the spell on a failure and wasting it.
• The winds whipping around you hedge out vapor, gas, and fog that can be dispersed by strong wind.
• You must use your bonus action to maintain this effect, and it cannot be activated again for 5 minutes once deactivated. The effect ends automatically after 1 minute.