Who is the Heir to Westmarch?

Two facts are confirmed: the player is the Heir to Westmarch, and there is an as yet unexplained connection between the player character and Diablo. Everything below is our analysis of what that framing sets up.

Heir to what, exactly

Westmarch is not a prize in Diablo V. It is Diablo's throne. An "heir" to a city ruled by the Lord of Terror inherits a claim that is worthless and a bloodline that is dangerous - which is a far more interesting starting position than "chosen one".

The connection

Blizzard flagged the connection and then stopped. That is a deliberate narrative hook. The series has repeatedly used the idea that proximity to a Prime Evil is inherited or transferred rather than chosen, so a bloodline reading is available - but it has not been stated, and we will not file it as fact.

What has been said since is about where the connection starts, not what it is. Narrative director Jennifer Hepler says the story begins when the Heir finds they can walk into Diablo's Terror Realm and come out alive - "which nobody else can do" - and that the bond, and how it helped Diablo win, unfolds over the course of the story. That is a developer statement; more on it in Diablo's victory will not stay off-screen.

Why it matters mechanically

If the player's tie to Diablo is narrative only, it changes cutscenes. If it touches systems - corruption, reputation with cults, how the procedural world reacts to you - it changes the game. Nothing about that has been confirmed.