Stormborn. Bred and raised to be the pinnacle of Drow cunning and Orcish brutality, Zuresh has the following racial traits:

Aggressive. As a bonus action, you can move up to your speed toward a hostile creature you can see. 

Fey Ancestry. You have advantage on saving throws against being charmed, and magic cannot put you to sleep. 

Slayer. In the first round of combat, she has advantage on attack rolls against any creature that hasn't taken a turn yet. If she hits anyone that round who was surprised, it is automatically a critical hit.  

Vessel of Lightning. After extensive training and praying to Talos, she has learned how to utilize her body as a vessel for the divine energy of the Storm god. She sets herself aside to allow his power to flow, and can cast up to three weather-like concentration spells at once while in her 'Storm Hollowed' form.

Divine Resurgence. After being defeated, the storm will revive her with half her max hit points with Witch Bolt, Lightning Lure, Chain Lightning, and Storm Sphere with all their effects doubled unless the book is destroyed before she is killed, which severs her connection to Talos. 

Spellcasting. The Thundermaul is a 9th-level spellcaster. Her spellcasting ability is Intelligence (spell save DC 17, +16 to hit with spell attacks). The Thundermaul has the following arcane spells prepared:
Cantrips (at will): Eldritch Blast, Lightning Lure, Thaumaturgy
1st level (5 slots): Witch Bolt, Fog Cloud, Disguise Self, Inflict Wounds, Ray of Sickness
2nd level (5 slots): Shatter, Arcane Lock, Beast Sense, Blindness/Deafness
3rd level (5 slots): Counterspell, Dispel Magic, Enemies Abound, Lightning Bolt
4th level (4 slots): Polymorph, Storm Sphere, Death Ward, Dimension Door
5th level (4 slots): Wrath of Nature, Cloudkill, Negative Energy Flood
6th level (4 slots): Disintegrate, Scatter, Chain Lightning
7th level (3 slots): Finger of Death, Sequester
8th level (3 slots): Control Weather, Antimagic Field
9th level (2 slots): Storm of Vengeance, Meteor Swarm

Storm Hollowed. Zuresh can use her Storm Sigil at the top of either hill to enter this state. She temporarily stores her soul in the sigil to allow Talos to enter her body and fight. While in this state, her body becomes resistant to all melee attacks, and is immune to magic attacks until her next round, lasting 1d6 turns. This allows her to use three weather-like concentration spells simultaneously. 

Gold Spear. Melee Weapon Attack: +10 to hit, reach 80 ft., 1 target. Hit:  8 (2d6 + 4) piercing damage. This spear was a staff of a sea witch that Zuresh purposed into a magical spear that returns to her once it hits its target. 

Orc Solidarity. (Recharge 1d6) She effortlessly commands the Orcs under her banner. Zuresh can unleash a battle cry to echo across the battlefield to temporarily increase the Orc's fighting spirit. All Orcs within 40' of her have a +10 to hit on their next series of attacks.

Tempest's Grip. Enemies entering the 20' space around Zuresh must make a DC 16 Dexterity saving throw or be tethered to her spell book as a Lightning Lure latches onto up to three targets at once, causing them to be Grappled until they can break free with a DC 15 Dex or Str save, or if she moves out of the 20' range.

Once she hits a quarter of her hit points, or all the Orcs are dead, she summons, or is gifted, a Storm Giant to assist with ending the group.

Mana Redirect. Anytime a spell of any basic arcane type (fire, cold, or lightning) is used on Zuresh or an Orc within 60' of her, that energy is sent back toward the caster.  This reaction can be used three times before she must return to the Storm Sigil. 

Dark Elf Deftness. Whenever hit with a melee attack and not in her Storm Hollowed form, any melee attack can have the damage reduced by 1d8 as a reaction. 

Zuresh Storm Hollowed can take 3 legendary actions. Only one can be used at the end of another creature's turn. She regains spent legendary actions at the start of her turn 

Teleport. Zuresh can disappear into the lightning strikes to a location 60' away without provoking an opportunity attack. 

Storm Mirror. Zuresh can inflict all damage she just took onto an enemy within 60' that she can see. 

Storm Hollowed (Costs 2 Actions). Upon touching a Storm Sigil hidden in the ground as a rune circle atop either of the cliffs, she can store her soul to allow Talos to take control for a short time. This will last 1d6 of her turns, and doubles her movement speed, while giving her a Fly speed of 80'.