Alwin, Nightmarish Overture

Innate Spellcasting. Alwin's innate spellcasting ability is Charisma (spell save DC 19). It can innately cast the following spells, requiring no material components:
At will: animate dead, bestow curse, darkness
3/day each: greater invisibility (self only), hunger of hadar, silvery barbs
1/day each: danse macabre

Legendary Resistance (3/day)
If Alwin fails a saving throw, it can choose to succeed instead.

Magic Resistance
Alwin has advantage on saving throws against spells and other magical effects.

Magic Weapons
Alwin's weapon attacks are magical.

Ventriloquism
Whenever Alwin speaks, it can choose a point within 60 feet; its voice emanates from that point.

Unusual Nature
Alwin doesn't require air, food, drink, or sleep.

Unworldly Concentration
Alwin can choose to forgo concentration on concentration-based spells. When this feature is used to cast a spell, the spell cast this way last for its maximum duration. This feature can be used twice a day.

Multiattack. Alwin makes one Rapier and uses its Dissonant Dirge once.

Rapier (Violin Bow). Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 7 (1d8 + 3) [slashing] damage plus 9 (2d8) [necrotic] damage. 
If the target is a creature, its hit point maximum is reduced by an amount equal to half the necrotic damage it takes.

Teleport
Alwin magically teleports, along with any equipment it is wearing and carrying, up to 120 feet to an unoccupied space it can see.

Dissonant Dirge
Alwin targets one creature it can see within 10 feet of it. The target must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. While frightened in this way, the target must take the Dash action and move away from Alwin by the safest available route on each of its turns, unless there is nowhere to move, in which case it needn't take the Dash action. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Enrapturing Etude
Alwin targets one creature it can see within 60 feet of it. The target must make a DC 19 Charisma saving throw. On a failure the target is charmed for 1 minute. The charmed target can repeat the saving throw if Alwin deals any damage to it. A creature that succeeds on the saving throw is immune to Alwin's Enraptured Etude for 24 hours.

Alwin, Nightmarish Overture can take 3 legendary actions, choosing from the options below. Only one legendary option can be used at a time and only at the end of another creature's turn. Alwin, Nightmarish Overture regains spent legendary actions at the start of its turn.

Encore (Costs 2 Actions)
Alwin attacks with its rapier or uses its Dissonant Dirge

Otherworldly Domination
Alwin uses Enrapturing Etude . Alternatively, it targets one creature charmed by it that is within 60 feet of it; that charmed target must make a DC 19 Charisma saving throw. On a failure, Alwin decides how the target acts during its next turn.

Teleport
Alwin uses its Teleport action.