Telepathic Bond. The fiend ignores the range restriction on its telepathy when communicating with a creature it has charmed. The two don't even need to be on the same plane of existence. In addition, it always has a link to its twin, no matter the distance..

Regeneration. The Leanan Sidhe regains 20 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water. If the fiend takes radiant damage or damage from holy water, this trait doesn't function at the start of the fiend's next turn.

Inherited Weaknesses. The Leanan Sidhe has inherited these weaknesses from its Vampiric father:
Forbiddance. Can't enter a residence without an invitation from one of the occupants.
Stake to the Heart. If a piercing weapon made of wood is driven into their heart while they are incapacitated, the Leanan Sidhe is paralyzed until the stake is removed.

Multiattack. The Leanan Sidhe makes two attacks, only one of which can be charm.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) slashing damage.

Charm. One humanoid the fiend can see within 30 feet of it must succeed on a DC 15 Wisdom saving throw or be magically charmed for 1 day. The charmed target obeys the fiend's verbal or telepathic commands. If the target suffers any harm or receives a suicidal command, it can repeat the saving throw, ending the effect on a success. If the target successfully saves against the effect, or if the effect on it ends, the target is immune to this fiend's Charm for the next 24 hours.

The fiend can have only one target charmed at a time. If it charms another, the effect on the previous target ends. (This does not conflict with Lover's Infatuation if Lover's Infatuation is called first or if the lover is deceased.)

Lover's Kiss. The fiend kisses a creature charmed by it or a willing creature. The target must make a DC 15 Charisma saving throw against this magic, extending the charm by another 24 hours and taking 1d6 psionic damage on a failed save, or half as much damage on a successful one. The target's hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target's HP max can not go below 1.

Etherealness. The fiend magically enters the Ethereal Plane from the Material Plane, or vice versa.

Lover's Infatuation (1/Day). The fiend magically calls it's lover, living or dead, to come to its aid. If living, he retains all his memories, but acts solely under the Leanan Sidhe's command, as if under an unbreakable charm. If dead, he acts as an undead servant. Either way, he retains all the skills, prowess, and stats that he had before. The called lover continues to serve the Leanan Sidhe until he is incapacitated or the Leanan Sidhe is defeated, thus breaking the charm.