Aeon's End
What does a Power card's POWER X number mean, and does it repeat the effect X times?
The designer explained the countdown, and it matches the rulebook's description of powers.
No — the number is a countdown. Each nemesis turn the power loses one token, and when the last token is gone the effect resolves once and the card is discarded. If the card has a To Discard cost, a player can discard it early by paying it during their main phase.