Dread Knight

Melee Weapon Attack: +12 to hit reach 5 ft. one target. Hit: 13 (2d6 + 6) slashing damage plus 14 (4d6) necrotic damage and the targets hit point maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the target finishes a long rest. The target dies if its hit point maximum is reduced to 0.

A fiery mote streaks from the dread knights finger to a point within 120 feet and blossoms into a 20-foot-radius sphere of black fire which spreads around corners. Each creature within the area makes a DC 16 Dexterity saving throw taking 63 (18d6) fire damage on a failed saving throw or half damage on a success. This damage ignores fire resistance and treats immunity to fire damage as fire resistance.

The dread knight magically creates a wall of ice on a solid surface it can see within 60 feet. The wall is flat 1 foot thick and can be up to 50 feet long and 15 feet high. The wall lasts for 1 minute or until destroyed. Each 10-foot section has AC 12 30 hit points vulnerability to fire damage and immunity to cold necrotic poison and psychic damage.

The creature then makes a DC 16 Dexterity saving throw taking 49 (14d6) cold damage on a successful save or half damage on a success.

A creature within 60 feet makes a DC 16 Constitution saving throw taking 70 (20d6) necrotic damage and falling prone on a failed save or taking half damage on a success.

A fell nightmare or wyvern magically appears in an empty space within 5 feet. The steed follows the dread knights commands and acts on its turn. It may attack on the turn on which it is summoned. It remains until the dread knight dismisses it as an action or it is killed.