Weathermage

Spellcasting. The Weathermage is a 15th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 20, +10 to hit with spell attacks). The Weathermage has the following Wizard spells prepared:

Cantrips (at will): Shocking Grasp 

1st level (4 slots): Chromatic Orb, Thunderwave

2nd level (3 slots): Gust of Wind

3rd level (3 slots): Lightning Bolt, Sleet Storm

4th level (3 slots): Ice Storm

5th level (2 slots): Cone of Cold

6th level (1 slot): Chain Lightning, Sunbeam

8th level (1 slot): Control Weather

Conjure Storm. As an action, the Weathermage can conjure storms. Each creature in a 70-foot sphere must make a Dexterity saving throw. If they fail, for each turn they stay in the sphere, they take 1d8 of each of the following damage types: lightning, thunder, cold, and bludgeoning. If they succeed, they take half damage. If a creature reenters the sphere, they must make a Dexterity saving throw or take 1d8 for each of the following damage types: lightning, thunder, cold, and bludgeoning. If they succeed, they take half damage. This effect lasts 4 hours.

Thunderous Travel. As a bonus action, the Weathermage can teleport through thunder. The Weathermage can teleport to a point within 300 feet of it and deal 1d6 thunder damage to each creature that was standing within 5 feet of it.

Quarterstaff. Melee Weapon Attack: +5 to hit, reach 5 ft. Hit: (1d6) bludgeoning damage. 

Electric Shield. If the Weathermage gets struck by lightning, it can use a reaction to cause an electric shield to form around it. Until the end of its next turn, any creature that makes a melee weapon attack against it has disadvantage and takes 1d8 lightning damage.