Hero items are the only treasures that are assigned to heroes.
Treasures like the Endurance Potion are not assigned to heroes and can be used without having a hero. Place those treasures face-up in your play area.
If a hero carrying a hero item dies, you must assign that hero item to another hero of your choice (it doesn't have to be one of your heroes).
In your example, you could have used the potion.
You are up early (or late)
Did I completely miss this in the manual?
BTW I assume the same applies when your hero dies and you don't have any heroes, the item goes to another player? What if in solo, do you discard it?
Anyway thx so much!