by Koey
There are 2 situations where you are active player.1. When it's your turn right before and after you put down a build card and before the next player is allowed to put down a card.
2. When Heroes are running through your dungeon.
When you allocated all the Heroes to all the entrance of the dungeon. The Bait phase is fully over and the Boss with the Highest XP goes first.
At that moment where you start moving Heroes that Boss will be active player. Any spells/activities he plays has priority over anyone else.
Hope this helps.