Spoilers: Her place beside Louen, and the quest item named in Update 2.2. No quest result.

Who she is in Total War
The Fay Enchantress leads Carcassonne, one of the four free Bretonnian legendary lords. The June 2022 Immortal Empires list places her there. She wields the Lore of Life, including healing, and the lord page gives her the unicorn Silvaron as a mount. Knights still need room to charge. Healing helps a regiment that has already been hurt. It does not open a path out of a surround. A Paladin supplies melee. Another Damsel can bring Beasts or Heavens if a second Life caster is the wrong coverage.
Her campaign uses Chivalry and the Peasant Economy with the rest of Bretonnia. Chivalry can call the Green Knight. Peasant recruitment competes with farm income. Those systems are the kingdom's, administered from Carcassonne in her campaign and from Couronne in Louen's.
The Lady's authority and the crown
The game's background makes her the Lady of the Lake's representative. Louen's accession had her consent, and Grail Knights owe service to the Lady. King and Enchantress are two offices. Alberic governs Bordeleaux and then sails from Bregonne. Repanse carries the Sword of Lyonesse on the Coast of Araby. None of those three campaigns moves her seat from Carcassonne.
Update 2.2 names her quest for Morgianna's Mirror and the building it requires, the Tower of the Enchantress. The notes fix the quest so that it completes on that tower rather than on any building. Morgianna's Mirror is the quest item's name in the patch. The Green Knight, in the Old World almanack, is the Lady's protector and appears to questing knights and in times of great need. The almanack leaves what he is among Bretonnia's mysteries.
The kingdom before Louen's reign
The Bretonnia almanack's present is Imperial Calendar 2276, fourteen dukedoms, Gilles le Breton's twelve battles, and the Lady's Grail. Athel Loren is not one of the dukedoms. A later design note puts 2276 a few decades before the Great War Against Chaos. The Fay of the Carcassonne campaign belongs to the Total War kingdom, with Louen already king at Couronne.
That earlier tabletop year is not a chapter of her Immortal Empires war. Age of Sigmar is a different world again. Her page stays with Carcassonne, the Lady, and the Life lore the game gives her.
A short story in Sylvania
Phil Kelly’s The Bone Cage is an unnumbered End Times short story. Black Library calls it a bridge between Sigmar’s Blood and The Return of Nagash. A cage of living bone carries holy men and women through Sylvania. The jacket names the Fay Enchantress of Bretonnia among the prisoners, and it names Mannfred von Carstein at the head of the procession. It also names the Grand Theogonist and does not give that priest another name. The prisoners try to read his purpose. The outcome stays in the story.
Carcassonne, the Lore of Life, and Louen’s court are the Total War Enchantress. The cage is one End Times scene. It is not her Immortal Empires start, and it is not the Bretonnia of Imperial Calendar 2276.
The Fay Enchantress: gameplay and availability · More character stories
Sources
- Immortal Empires DLC Ownership Guide — SEGA — support.sega.com
- Immortal Empires starting positions, a prologue — Total War — totalwar.com
- Update 2.2.0 — Total War — totalwar.com
- Old World Almanack: Discover Bretonnia — Warhammer Community — warhammer-community.com
- The Bone Cage — Black Library — blacklibrary.com
- Immortal Empires DLC Ownership Guide — support.sega.com
- Total War: WARHAMMER — A New Player Survival Guide & FAQ — community.creative-assembly.com
- Total War: WARHAMMER — Bretonnia — store.steampowered.com