Cultist Grand Executioner

Dark Devotion. The Cultist Grand Executioner had advantage on saving throws against being charmed or frightened.

Powerful Build. The Cultist Grand Executioner counts as one size larger when when determining its carrying capacity and the weight it can push, drag, or lift. It also has advantage on all strength based checks and saving throws.

Legendary Resistance (3/Day). If the Cultist Grand Executioner fails a saving throw, it can choose to succeed instead.

Multiattack. The Cultist Grand Executioner makes two Sacrificial Cleaver attacks.

Sacrificial Cleaver. Melee Weapon Attack: +12 to hit, reach 10 ft., # target. Hit: 19 (2d12 + 7) slashing damage. targeted creatures must make a DC 16 Strength saving throw or be pushed back 15 ft. 

Devotee's Fury. The Cultist Grand Executioner enters a state of intense rage. for the next minute this creature deals an additional 12 (2d10) radiant or necrotic damage when making a melee weapon attack. in addition, the Cultist Grand Executioner becomes resistant to all physical damage (Bludgeoning, Piercing and Slashing) from both magical and non magical sources as well as Radiant and Necrotic damage.

Opportunity Attack. The Cultist Grand Executioner takes an attack of opportunity when a creature moves through it's melee range radius.

Crushing Parry.  When the Cultist Grand Executioner is struck with a melee weapon attack, it may use a reaction to reduce and return damage delt equal to 1d10 + its Strength modifier. when an affected creature has its damaged reduced to 0, must succeed a DC 16 Strength Saving throw or be pushed back 10 ft. and knocked prone. 

The Cultist Grand Executioner can make 3 legendary actions, choosing from the options below. Only one legendary option can be used at a time and only at the end of another creature's turn. The Cultist Grand Executioner regains spent legendary actions at the start of it's turn.

Multiattack (Costs 1 Action). The Cultist Grand Executioner makes two Sacrificial Cleaver attacks.

Reckless Charge (Costs 2 Actions). The Cultist Grand Executioner charges using its full movement speed in a straight line. all creatures in the 10ft by 50ft line take 2d10 force damage and must make a DC 15 Strength saving throw. on a fail, the affected creatures take the full damage and are knocked prone. on a success the affected creature takes half the damage and isn't knocked prone. This action does not provoke attacks of opportunity.