Do we need to define explicitly who, when, and how long the possession occurs, or is this entirely up to the Narrator? The mechanic could be random dice roll for any or all of these aspects to make it more “fair”.

Just trying to see where you’re at with the intention of this Proposal, since I’d have to implement it. ;-)

To clarify my question: is it up to the Narrator to pick a person at the Narrator’s whim?

If it’s tracked gamestate then it can’t be changed until the rules provide a way for it to be changed.

Ah, got it, so it’s left to another Proposal to propose the mechanic for choosing all of that.