Crimson Monstrosity

Magic Resistance. The Crimson Monstrosity has advantage on saving throws against spells and other magical effect.

Call of the Hand. The Crimson Monstrosity responds to commands given to it by Principles of the Cult of the Crimson Hand. They are immune to spells that would order it to attack allies.

Sunlight Sensitivity. The Crimson Monstrosity has disadvantage on attack rolls whilst in direct sunlight, as well as on Wisdom (perception) checks that rely on sight.

Life Hunger. If a creature within 60 feet of the Crimson Monstrosity regains hit points, the Monstrosity gains two benefits until the end of its next turn: it has advantage on attack rolls, and its attack deals an extra 22 (4d10) necrotic damage on a hit.

Multiattack. The Crimson Monstrosity makes three attacks with its Claws and one with its Bite.

Raking Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 24 (5d8 + 8) slashing damage. 

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 24 (6d6 + 8) piercing damage. 

Sonic Roar. The Crimson Monstrosity inhales sharply then lets out a booming roar that causes the very air to vibrate visibly. Any creatures in a 120 ft. cone must succeed a DC 18 Dexterity save or take 65 (12d10) force damage and are knocked prone, taking half on a successful save and aren't knocked prone. Any creature that is within 10 ft. of the Crimson Monstrosity are deafened for 1d4 rounds.

Blood Spray (Reset 5-6). The Crimson Monstrosity sprays a cloud of blood in a 20 ft. radius, all creatures caught in the cloud must succeed a DC 18 Constitution saving throw or take 51 (12d8) poison acid damage and are poisoned, taking half damage on a successful save and aren't poisoned.

The Crimson Monstrosity can take 3 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. The Crimson Monstrosity regains spent legendary actions at the start of their turn.

Bite (Costs 1 Action). The Crimson Monstrosity makes a bite attack.

Unnatural Speed (Costs 1 Action). The Crimson Monstrosity can move up to 20 ft., this movement can include its climbing speed.

Leaping Claw Attack (Costs 2 Actions). The Crimson Monstrosity can leap up to 15 ft. towards a creature and make a claw attack. By doing so the Monstrosity deals an additional 15 (3d8) slashing damage on a hit and the creature is knocked prone.

Sonic Roar (Costs 3 Actions). The Crimson Monstrosity makes a Sonic Roar attack. The Crimson Monstrosity inhales sharply then lets out a booming roar that causes the very air to vibrate visibly. Any creatures in a 120 ft. cone must succeed a DC 18 Dexterity save or take 65 (12d10) force damage and are knocked prone, taking half on a successful save and aren't knocked prone. Any creature that is within 5 ft. of the Crimson Monstrosity are deafened for 1d4 rounds.