When multiple hidden cards are controlled at the same battlefield and triggered by an opponent's unit moving there, can the controller activate both hidden cards consecutively before the opponent can react, or does the opponent get priority to react between each hidden card activation?

Ruling: You can play multiple reactions consecutively as long as you hold priority and do not pass. However, in the specific example given, the opponent has first priority in the showdown, so you can only react after they pass priority to you.

Sequence:

• Opponent moves unit to the battlefield (opponent has first priority in the showdown)
• Opponent passes priority
• You can now activate your first hidden card
• If you hold priority, you can immediately activate your second hidden card without passing
• Once you pass priority or a chain fully resolves, priority returns to the opponent

Nuances:

• You must explicitly state you are holding priority if you want to play multiple reactions consecutively (especially in tournament play)
• When a chain finishes resolving, priority passes to the other player
• Unless there are other trigger effects, the opponent controls when you first get priority in this scenario