In Celtic folklore, the Irish leanan sídhe is a beautiful woman of the Aos Sí (or fairy folk) who takes a human lover. Lovers of the leanan sídhe are said to live brief, though highly inspired, lives. The leanan sídhe is generally depicted as a beautiful muse, who offers inspiration to an artist in exchange for fame and glory; however, this exchange frequently results in madness for the artist, and often premature death.
They seek the love of mortals. If the object of their affection refuses, she must be their slave; if they consent, they are hers and can only escape by finding another to take their place. The fairy lives on with their life, leaving the object of a leanan sidhe's affection to waste away.
The name comes from the Gaelic word "leannan," a sweetheart, concubine or favorite. Also, Sídhe, "of the fairy mounds."
Leanan Sidhe can only be acquired through fusion. She appears as an enemy within the Nakano Boundless Domain and Protopia's Valuable Challenge instances.
Shin Megami Tensei: Strange Journey
"A beautiful faerie of Irish foklore whose name means "faerie mistress." She drains the life of her lovers in return for granting them artistic inspiration."
Devil Summoner 2: Raidou Kuzunoha vs. The Soulless Army
"A beautiful fairy of Irish folklore that yearns for the love of a human man. She drains the life of her lovers in return for granting them artistic inspiration."
—Gouma Den devil chart
Persona 4
Leanan Sidhe becomes available once the protagonist reaches Level 42. As with all Personas of the Lovers Arcana, she can only be acquired through fusion.
The Animation
Leanan Sidhe was used by Yu in Episode 12. She was used to cast a spell through Shadow Mitsuo's Ear by a whisper to bewilder and enrage Shadow Mitsuo. She is also the Persona that represents the bond between Yu and Rise.
Persona 5
"A beautiful fairy of Irish lore that yearns for the love of a human man. She drains the life of her lovers in return for granting them artistic inspiration."
—Persona 5 background
Leanan Sidhe is the third Persona of the Lovers Arcana and appears as a Shadow in Kaneshiro's Palace and in the Kaitul area of Mementos, with the title "Jealous Lover." She is the first Persona to learn the Psio and Mamudo skill, and the first Persona usable to the protagonist to learn the Mapsi skill and Eiga skill. When itemized through Electric Chair execution in the Velvet Room, Leanan Sidhe yields a Recarm skill card.
The Animation
Leanan Sidhe made a brief cameo in Episode 7 as a fusion, and in Episode 8, she was used by Ren to cast an Agi spell against Shadow Madarame .
Devil Survivor 2
"A beautiful faerie of Irish lore whose name means "faerie mistress." She drains the life of her lovers in return for granting them artistic inspiration."
—Devil Survivor 2 compendium
Shin Megami Tensei: Liberation Dx2
"A beautiful fairy of Irish lore whose name means "fairy mistress." She drains the life of her lovers but in return grants them with artistic inspiration."
