Does Ember Monk's +2 ability stack if multiple cards are played from hidden in the same turn, and does it work with hidden cards from any battlefield?

Ruling: The +2 boost lasts until end of turn and stacks for each card played from hidden. It doesn't matter which battlefield the hidden cards were on.

Sequence:

• Play first card from hidden: Ember Monk gets +2
• Play second card from hidden same turn: Ember Monk gets +4 total
• Boost persists until end of turn

Nuances:

• You cannot play a card the same turn you hide it
• This stacking mechanic also applies to similar abilities like Ravenbloom Student
• Playing more than 2 cards from hidden in a turn is difficult in practice