Annihilator

Divine Smite: When the Annihilator hits a creature with a melee weapon attack, it can expend one spell slot to deal radiant damage to the target, in addition to the weapon’s damage. The extra damage is 2d8 for a 1st-level spell slot, plus 1d8 for each spell level higher than 1st, to a maximum of 5d8.

Magic Resistance: The Annihilator has advantage on saving throws against spells and other magical effects.

Stormstrike Weapons: The Annihilator's weapon attacks are magical and deal an extra 2d8 lightning damage (included in the attack).

Multiattack: The Annihilator makes two attacks with its Thunderstrike Hammer.

Thunderstrike Hammer: Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 21 (3d8 + 7) bludgeoning damage plus 9 (2d8) lightning damage.

Storm Shield Bash: Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) bludgeoning damage and the target must succeed on a DC 19 Strength saving throw or be knocked prone.

Thunderous Charge (Recharge 5-6): The Annihilator moves up to its speed in a straight line. During this move, it can move through the space of any creature smaller than Huge. Each creature whose space the Annihilator moves through must make a DC 19 Dexterity saving throw, taking 27 (6d8) lightning damage on a failed save, or half as much damage on a successful one. If the Annihilator ends this move within 5 feet of a creature, it can make a Thunderstrike Hammer attack against that creature as a bonus action.

Divine Challenge: The Annihilator targets one creature it can see within 30 feet. The target must succeed on a DC 19 Wisdom saving throw or be frightened until the end of the Annihilator's next turn.

Divine Retribution: When the Annihilator is hit by a melee attack, it can cause lightning to strike the attacker. The attacker must make a DC 19 Dexterity saving throw, taking 18 (4d8) lightning damage on a failed save, or half as much on a successful one.