If Fiora attacks a battlefield with 1 unit and 1 hidden card, her might doubles. If the opponent then reveals the hidden card (Pakaa Cub) as a unit, does her might get reduced back to normal?

Ruling: Once Fiora's ability triggers and goes on the chain, her might will double when it resolves. The trigger condition ("one on one") is checked when the ability triggers, not when it resolves, so revealing the hidden card afterward does not prevent the might doubling.

Sequence:

• Fiora attacks a battlefield with 1 unit and 1 hidden card
• Her ability triggers and goes on the chain (condition met: only 1 unit visible)
• Opponent cannot flip the hidden card as a reaction to prevent the trigger
• Ability resolves and her might doubles

Nuances:

• The "one on one" condition is part of the trigger condition, not the effect, so it's checked at trigger time only
• Once the ability is on the chain, revealing additional units will not undo or prevent the might doubling