Spoilers: Character background and campaign premise; no Grand Scheme battle outcomes or campaign ending.

The trickster of Tzeentch
The Changeling embodies Tzeentch's urge to deceive and interfere. He can imitate other beings, hiding the identity behind the disguise. Even his own shape remains concealed beneath a cloak, and his true appearance is a mystery.
His deceptions encourage discord and war. The suffering that follows is part of the mischief to him: conflict creates more opportunities to impersonate, mislead and upset those who believe they understand their allies or enemies.
Borrowed faces and borrowed strength
In battle, the Changeling takes an opponent's shape and uses borrowed power against his foes. His transformations make the familiar unreliable. A figure that looks like a known ally or ruler can conceal Tzeentch's trickster.
The Deceivers in Total War
Total War: Warhammer III gives the Changeling command of The Deceivers, a Tzeentch faction introduced with Shadows of Change. Trickster Cults and Schemes turn his appetite for disruption into a campaign across Immortal Empires. The player chooses which plots succeed and which identities he collects.
A form nobody can swear to
The Shadows of Change store account calls the Changeling the shape-shifting agent of misrule, the part of Tzeentch that deceives rather than the part that prophesies. He can wear the form of legendary characters from the noble to the fearsome. None but perhaps Tzeentch know the true form. The trickery is said to be capable of deceiving the Dark Gods themselves: mirrored foes, false allies, empires pulled apart from inside.
That is a different gift from Kairos’s two heads. The Oracle sees along time and casts. The Changeling is the doubt in a familiar face. A figure that looks like a known lord can be the trickster, and the campaign’s stolen identities are that idea with a button on it.
Theatres, Schemes, and the other Tzeentch lord
The Deceivers come with The Changeling – Shadows of Change, separate from Kairos’s base-game faction. The campaign is playable in Immortal Empires and in The Realm of Chaos. The Blue Scribes ride in the same pack. The world, for this lord, is divided into Theatres. Minor schemes soften a Theatre. A grand scheme ends it in a battle. Cultists, stolen names, and buildings raised where they do not belong are the work between those battles.
Kairos keeps a spellcaster’s faction and meddles through cults and Changing of the Ways. The Changeling barely needs the land to be his. Update 9.0 lets Archaon subjugate either of them and hand the regions to a Tzeentch vassal. Subjugation does not reveal the face under the cloak. The store account still leaves that face with Tzeentch, if with anyone.
The Changeling: gameplay and availability · More character stories
Sources
- The Changeling – Shadows of Change — store.steampowered.com
- Corrupt, Coerce, and Concoct with Shadows of Change — warhammer-community.com
- The Changeling — Shadows of Change — Total War — totalwar.com
- Update 9.0 release notes — Total War — totalwar.com
- Immortal Empires DLC Ownership Guide — support.sega.com