Crow Mauler

Dread Stalker. The Crow Mauler is an creature driven by pure desire to exterminate all life it sees, once it has its sights on it's prey it will stop at nothing to slaughter them, and will always know the general direction they are.

Terrifying Presence. A creature being hunted by the Crow Mauler can feel it's killing intent, even if they cannot see it, and will know it's being stalked by them. They must succeed on a DC 14 Wisdom Saving Throw or become frightened the next time the Crow Mauler is within line of sight of them. The creature can reroll the saving throw at the end of their turn, on a success, they are immune to being frightened by Terrifying Presence.

Unstoppable. This creature's movement speed cannot be slowed down, and has advantage on spells and effects that would restrict its movement and actions.

Bone Crusher. When the Crow Mauler lands a Critical Hit when attacking with it's Maul, the creature hit with the attack must make a Constitution saving throw against the damage halved (Minimum 10), on a failure, they suffer a broken limb, roll odds or evens to decide if its an arm or a leg. If it's an arm, they are unable to benefit from aspects that would affect them from having that amount of hands (such as wielding two handed weapons or holding something in their off hand) and when they attempt to cast a spell of that has somatic components, they must make a Dexterity check of at least 10 + the level of the spell, or just 10 if casting a cantrip. If it's a leg, their speed is halved for each leg broken, and if benefits to armor class from their dexterity is also decreased by half their total dexterity. Broken Limbs can be healed by restoration spells of at least 2nd level.

Malphas' Failsafe. When the Crow Mauler reaches 0 hit points, it rises with half it's hit points as temporary hit points, and always has Foresight and Cawll of the Slaughter available. Each turn, the Crow Mauler takes 4d6 radiant damage.

Multiattack. The Crow Mauler either makes three times with its Maul, one time time with its Maul and one time with it's Peck, or one time with it's Maul and one time with its Flock of Crows.

Maul. Melee Weapon Attack: +11 to hit, reach 5 ft., 1 target. Hit:  (1d12 + 6) bludgeoning damage. 

Flock of Crows. Ranged Spell Attack: +9 to hit, range 80 ft., 1 target. Hit: (3d4 +4) piercing damage. Creatures hit must succeed on a DC 16 Constitution Saving Throw or become blinded for 1 minute. Creatures can reroll this save at the end of their turn, possibly ending the effect.

Peck. Melee Weapon Attack: +11 to hit, reach 5 ft., 1 target. Hit: 18 (4d6 + 6) piercing damage. A creature reduced to 0 hit points with this attack is instantly beheaded.

Bad Omen. When the Crow Mauler has Foresight available, it can shine it's eye onto all creatures within 15 ft. of it, haunting them with visions of their demise. All creatures within 15 ft. of it that can see must make a DC 14 Wisdom saving throw or become frightened.

Cawll of the Slaughter (Recharge 5-6). The Crow Mauler bellows out a terrifying croak, and has set it's sights on a singular unfortunate prey. When it moves towards the creature it has its sights on, it treats movement towards that creature as if it had only moved half that distance, and attacks against that creature deal an extra 1d6 damage when they hit. This effect applies until the end of the Crow Mauler's next turn.

Right Behind You. When The Crow Mauler is within 5 ft. of a Flock of Crows, it can teleport to another one within 60 ft. of it.

Foresight (Recharge 6). This creature can reroll any d20 roll it makes, or force another creature within 60 ft that it can see to reroll a d20 roll they make. 

The Crow Mauler has 3 Legendary Actions.

Maul. The Crow Mauler makes one Maul attack.

Flock of Crows. (Costs 2 Actions) The Crow Mauler makes one Flock of Crows attack.

Peck. (Costs 2 Actions) The Crow Mauler makes one Peck attack.

Foresight. (Costs 2 Actions) The Crow Mauler attempts to recharge it's Foresight reaction.