Does anyone know what the threat cost of a sword-thained hero would be?

Cards like " The Fall of Gil-Galad ", " The Great Bridge " and " Local Trouble " all reference hero threat cost. FAQ 1.40 ("Unless specified by a card effect, or granted player choice, the letter 'X' is equal to 0") implies it might be 0 - for the first two at least - but I'm not certain.

EDIT: Just found the answer: https://community.fantasyflightgames.com/topic/182402-i-had-a-thought-sword-thain/?p=1694826 - typical, thought I'd searched thoroughly!