Blind One

Telepathy. The Blind One can communicate telepathically to creatures it can sense, and can detect the presence of, but not exact location of, sentient creatures within 120ft.

Keen Hearing and Smell. The Blind One has advantage on Wisdom (Perception) checks that rely on sound or smell.

Charge. The Blind One rushes 15ft forward in a straight line. Any Medium or smaller creature caught in the path must make a DC 15 Dexterity saving throw or be knocked prone and take 28 (4d10+6) Bludgeoning damage. On success, the creature remains standing and takes half damage.

Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., 1 target. Hit: 19 (3d8 + 6) Bludgeoning damage. 

Frightful Presence. Each creature of the Blind One's choice that is within 120 feet of the Blind One and aware of it must succeed on a DC 14 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the Blind One's Frightful Presence for the next 24 hours.

The Blind One 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 Blind One regains spent legendary actions at the start of its turn.

Detect. The Blind One makes a Wisdom (Perception) check.

Command. The Blind One telepathically attempts to cast Command on a creature it can sense. The target must succeed on a DC 14 Wisdom saving throw or follow the Blind One's command.

Charge (Costs 2 Actions). The Blind One makes a charge attack.