Blessing of Drascus: Thunder Bringer- This creature is coated in electricity causing all of its weapons to deal Lightning Damage on top

Electrified Perception: This creature gets 5 reactions per round. This creature also cannot be surprised

Spellcasting. 
Cantrips (at will): [Shocking Grasp]
1st level (12 times per day): [Witch Bolt]

6th level (10 times per day):[Chain Lightning], [Lightning bolt (At 6th Level)]

Legendary Resistances (5 times/day): When this creature fails a saving throw, it can choose to succeed instead.

Thunderous Fist Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 36 bludgeoning damage.

Beginning of The End Melee Weapon Attack: +16 to hit, reach 5 ft. radius, Hit: 39 (7d10) bludgeoning damage.

The Big Bang Melee Weapon Attack: +16 to hit, reach 600 ft. radius, Hit: 39 (7d10) bludgeoning damage. Miss: 13 (2d12) Thunder Damage

Storm of Void Lightning Melee Weapon Attack: +16 to hit, reach 600 ft. radius, Hit: 39 (7d10) Slashing & Necrotic damage.

Void Star Arrows Ranged Weapon Attack: +12 to hit, range 150/600 ft., 3 targets. Hit: 9 [roll]2d8[/roll] piercing, necrotic damage.

Breaker of Minds: While grappling, this creature can use a bonus action to spend up to 30 ft. of movement, dealing 1d6 psychic damage for every 10 ft. spent.

Great Weapons Master Attack: On this creatures turn, when it scores a critical hit with a melee weapon or reduce a creature to 0 HP with one, it can make one melee weapon attack as a bonus action.

Recover Vitality: This creature has a pool of ten d10s. As a Bonus Action, it can expend dice from the pool, roll those dice, and regain a number of HP equal to the roll’s total. It regains all the expended dice at midnight or every 3 rounds if its storming

Second Wind: Once per short rest, you can use a bonus action to regain 2d100 + 30 HP.

Thunderous Counter: If an attack is Declared the creature, if within 5 ft. of the attacker this creature may throw the creature into the ground summoning a lightning bolt on them dealing 6(1d10+1) lightning damage.

Dodge Roll: This creature once every round may dodge 1 attack that is physically there, mental attacks cannot be dodged, when dodged the creature takes 0 damage. This also leaves a trail of Electricity where the creature rolled from.

Glacier Shield: This creature summons a shield blocking the attack (Taking half damage) and deals 7(2d8) cold damage

This creature can take 10 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. This creature regains spent legendary actions at the start of its turn.

Thunderous Clap [Costs 3 Actions]: The creature claps sending a thunderous sound that deals 24 (3d10+2) electric, and wind damages.

Electrical Field [Costs 6 Actions]: This creature may create a 30 ft. Radius field of electricity

Thunderous Roar [Costs 3 Actions]: this creature may let out a thunderous roar dealing 17 (2d10+3) and forcing concentration checks on any concentration spells.

Voidfire Healing [Costs 10 Actions]: This creature slams it's hand against its chest as a burst of Voidfire goes into it healing (3D10+10)

The creature can take mythic actions after being damaged past a certain threshold. These special actions can be taken only once over the course of battle, and cannot be prevented.

Thunder Titans Fist (330 HP): When this creature is below 330 HP it can summon from the heavens the fist of the Thunder titan and strike down on his enemies dealing (10d10+20) Lightning damage

Lightning Spear (220 HP):  When this creature gets below 220 HP it can create a spear of Lightning and send it flying at a single target dealing (5d20+12)

Void Lightning Explosion(110 HP): When this creature is under 110 HP it can end its own life to create an 800 ft. radius explosion which deals (1d100) Lightning Damage and (4d12) Force Damage