Spoilers: Game titles and the Gunnery School. No dragon's battle and no campaign ending.

Who she is in Total War
Elspeth leads Wissenland & Nuln. Elspeth – Thrones of Decay unlocks her, and the legendary hero Theodore Bruckner, for Immortal Empires and for a Realm of Chaos campaign that does not follow the Ursun story. Creative Assembly's introduction calls her the Dark Lady of Nuln to some and the Graveyard Rose to others, and a respected advisor to Elector Countess Emmanuelle von Liebwitz. The store page also calls her a magistrix of the Amethyst Order.
She is a Lore of Death caster with a scythe, and she can take the field on a Carmine Dragon. The Gunnery School turns Schematics into upgrades for gunnery and artillery. Field Testing opens the Amethyst Armoury, where Nuln's weapons and her Death magic meet. Gardens of Morr, placed in suitable friendly or neutral Empire settlements, let her army travel between them at a cost and on a cooldown. An enemy who takes the settlement can take the garden with it.
Theodore Bruckner
The same introduction calls Theodore Bruckner the Hand of Judgement. He is the headsman and Judicial Champion of the Elector Countess of Nuln, a melee hero who also stands against political opponents of the countess. The Wissenland play page also speaks of him as the Hound of Judgement. Both titles sit on his role in Nuln. He joins an Empire army. He does not open a second Empire legendary-lord campaign.
Franz still rules from Reikland. Gelt still runs the colleges from Cathay. Volkmar's Cult and Boris's Temple of Ulric are other offices. Elspeth's alliance with Nuln is the gunpowder office. A player's defence of the Empire through the gardens is a campaign route, not a chronicle of Emmanuelle's court.
Nuln in the game and in the novels
The End Times book The Fall of Altdorf is about the emperor and Kurt Helborg. It is not listed here as Elspeth's novel. Daemonslayer, the Gotrek & Felix book that introduces Malakai Makaisson and a living Ulrika, is a dwarf expedition, not her Gunnery School.
Age of Sigmar is a later setting. Elspeth's account here stays with the Empire of the Total War campaigns: Death magic, the dragon, the school, and the gardens. What a campaign does with Wissenland stays in that campaign.
Elspeth von Draken: gameplay and availability · More character stories
Sources
- Immortal Empires DLC Ownership Guide — SEGA — support.sega.com
- Thrones of Decay: Introducing Elspeth von Draken — Total War — totalwar.com
- Elspeth – Thrones of Decay — Total War — totalwar.com
- Elspeth – Thrones of Decay — Total War on Steam — store.steampowered.com
- Thrones of Decay: Introducing Elspeth von Draken — Creative Assembly — community.creative-assembly.com