Cultist Berserker

Dark Devotion. The cultist berserker has advantage on saving throws against being charmed or frightened. 

Reckless. At the start of its turn, the cultist berserker can gain advantage on all melee weapon attack rolls during that turn, but attack rolls against it have advantage until the start of its next turn.

Agonizing Overpower. In addition to strength, the cultist berserker adds its charisma modifier to its melee damage. (This damage is calculated in the actions description)

Multiattack. The cultist berserker makes two attacks with its preferred melee weapon.

Sickle. Melee Weapon Attack: +6 to hit, reach 5 ft., 1 target. Hit: 9 (1d4 + 7) slashing damage. 

Shortsword. Melee Weapon Attack: +6 to hit, reach 5 ft., 1 target. Hit: 10 (1d6 + 7) piercing damage.