Bloodstorm Sorceress

Legendary Resistance (3/Day). If the Bloodstorm Sorceress fails a saving throw, she can choose to succeed instead.

Spellcasting. The Bloodstorm Sorceress is a 7th level spellcaster. Its spellcasting ability is Wisdom (spell save DC 18, +8 to hit with spell attacks). The Sorceress has following spells prepared:

Cantrips (at will): encode thoughts, lightning lure, blade ward, chill touch

1st level (4 slots): absorb elements, chromatic orb, hex

2nd level (4 slots): blindness/deafness, darkness, gust of wind, see invisibility

3rd level (3 slots): counterspell, fly, lightning bolt

4th level (3 slots): elemental bane, locate creature, 

5th level (3 slots): antilife shell, control winds

6th level (2 slots): chain lightning

7th level (1 slot): reverse gravity 

Sanguine Hex. As a bonus action, the Sorceress senses the lifeblood draining from wounded creatures within 30 ft and places a hex that encourages blood-flow to the wound. The Sorceress chooses two available targets to mark with her hex. The afflicted creatures have disadvantage on Constitution saving throws until the start of their next turn. The Sorceress can have a maximum of 3 Sanguine Hexes on targets at any one time.

Tempest of Blood. A churning storm cloud forms, centered on a point the Sorceress can see and spreading to a radius of 180 feet. Red lightning flashes in the area and droplets of blood start to fall like fine rain. Each creature under the cloud (no more than 5,000 feet beneath the cloud) when it appears must make a DC 18 Constitution saving throw. On a failed save, a creature takes 19 (4d8) lightning damage and becomes frightened for 5 minutes. A creature takes half damage on a successful save.

Each round the Sorceress maintains concentration on this spell, the storm produces different effects on her turn. In addition, at the end of each round, the tempest emits a wave of concussive force centering on the Sorceress. Each creature within 60 feet must make a DC 17 Dexterity saving throw or be pushed back 20 ft and knocked prone.

Round 2. Bloody rain falls from the cloud. Each creature within range of the tempest and not under cover takes 11 (3d6) necrotic damage.

Round 3. You call six bolts of lightning from the tempest to strike six creatures or objects of your choice beneath the tempest. A given creature or object can't be struck by more than one bolt. A struck creature must make a DC 18 Dexterity saving throw. The creature takes 27 (6d8) lightning damage on a failed save, or half as much damage on a successful one.

Lightning Rod. Melee Weapon Attack: +6 to hit, reach 5 ft., 1 target Hit: 14 (4d6) bludgeoning damage and 4 (1d8) lightning damage. 

The Bloodstorm Sorceress can take up to 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. She regains spent legendary actions at the start of her turn.

Cantrip (1 action). The Sorceress casts a cantrip.  

Obscured by Rain (1 action). The Sorceress can move half her movement (15 ft walking or flying) without provoking opportunity attacks.

Blood Drain (2 actions). The Bloodstorm Sorceress attempts to drain the life force of two creatures within 30 ft. They must succeed on a DC 18 Constitution saving throw or take 28 (8d6) necrotic damage on a failed save, or half as much damage on a successful one. The Sorceress regains hit points equal to half of the total damage dealt.