Event Decks are a brand new feature in the game. When you designate a Planeswalker to a node, you will now be asked to set an Event Deck with that node, in addition to the Planeswalker.
This lets us do two things: 1- Match you against decks made for this event 2- Ensure that your deck fits within the deck building restriction for the event. That’s right - you will now only fight decks made for the current event, and no longer a random selection from your opponent’s roster. This means that in events that require playing specific creature types, for example, your opponent will have had to make the same choices you did when selecting your deck.
We hope this will make these events more fair in that you will not have to fight decks that are clearly not made to fit with the requirements in mind.