If Watcher dies and then a hidden unit is revealed later in the same turn at the same battlefield, is the hidden unit debuffed by Watcher's effect?

Ruling: Watcher only reduces the might of units currently on the board when it is played. The debuff does not persist after Watcher dies, and does not apply to units that enter or are revealed after Watcher is gone.

Nuances:

• Watcher's effect is not a persistent anthem/emblem effect that continues after it leaves play
• The debuff only affects units present at the moment Watcher's effect applies