Ancestors forbid is a Kencyr expression, an expletive or invocation. It's used by Jame twice so far, both in Seeker's Mask: the first time is in inside voice, and sarcastic:
She'd had to sit there in that hideous pink dress, not permitted to eat, drink, or (ancestors forbid) talk […]
while the second is an exclamation on hearing that the priests wanted to establish a heirocracy after the fall.
Ardeth also says this when arguing for the Northern Host to march against the Waster Horde:
We must support our own people, even if—Ancestors forbid—that only means gathering their bones for the pyre.
- ↑ Seeker's Mask, Part III: The Riverland: 55th–58th of Spring, Chapter II
- ↑ Seeker's Mask, Part III: The Riverland: 55th–58th of Spring, Chapter VI
- ↑ Dark of the Moon, Chapter 6: The High Council—Gothregor: 8th–10th of Winter