For storm mastery I think it should be based off of weather report which is a stand from jjba that can manipulate the weather.
Optional: When the user equips it and goes into the map the stand appears a few inches behind them and never leaves their side.
Obtainment: Strike 400 or 500 people with lightning
Moves:
E - Lightning clouds: Create 2 dark grey clouds on the left and right side high above the player. Clouds go where they go. Every 4 seconds they strike the nearest target. Ragdolls and knockback. 9 dmg each strike. Can be hit out of ability. 20 second cooldown. Last 10 seconds(?)
Q - Cloud Hover: Ride on top of a cloud and fly. Can't hit during ability. last 20 seconds. Can be hit out of ability. 17 second cooldown. For the visuals I was thinking Goku's cloud from dbz but make it white and add a white trail that fades, make it look as cloudy as possible.
Alternative for Q - Poison Frog Rain: User gains a purple aura around them and creates a dark slightly large cloud above them that follows them. The cloud rains frogs that have a purple aura around them too. The frogs are blue and if they are touched the person who touched them gets stunned and punched with a faint purple aura around them. This ability last 8 seconds and the frogs and cloud fade away after ability is over. Each time the player touches a frog they take 7 dmg. 25 second cooldown.