Rule 103.1
Cards in a player’s deck or rules of a Game Mode may indicate additional choices to be made while building the deck. Example: A unit reads in part “If [Name] is in your deck, choose 3 different legends in addition to your starting legend.” This decision is made while building the deck. Example: The rules of a game mode read in part “Choose an additional Chosen Champion with a different Champion Tag and Domain than your Champion Legend. Place it in the Champion Zone at the start of the game alongside your other Chosen Champion. Your deck’s Domain Identity includes that additional Chosen Champion’s Domain, if applicable.” The Chosen Champion chosen this way is decided while building the deck.