Who Are the Tarnished?

The Tarnished are people who once lived in the Lands Between under the light of the Erdtree, but were exiled and stripped of that light - the game calls it losing "grace." Being Tarnished isn't a species or a title so much as a punishment: at some point in the past, these people were sent away and lost their connection to the Erdtree's guidance, along with any hope of dying a real death.

When the game opens, that has just changed. The Elden Ring - the source of order in the Lands Between - has been shattered, the demigods who held its pieces have gone mad or gone to war, and grace itself has started calling the Tarnished back across the fog to the Lands Between. You play as one of these returning exiles.

Why does anyone want them back?

A cryptic, tiny figure called a Finger Reader explains it early on: the shattering left a vacancy. Whoever gathers the scattered fragments of the Elden Ring (the Great Runes, each held by a demigod) and repairs it can become the new Elden Lord. The Tarnished are being summoned as candidates for that role - not because anyone particularly likes them, but because the old ruling family has torn itself apart and someone needs to fix what's broken.

Not just one character

Importantly, "Tarnished" describes many people, not one chosen hero - other Tarnished are wandering the Lands Between at the same time you are, some friendly, most not. That's part of why multiplayer invasions and cooperative summons make sense within the story: everyone you meet answered the same call.