420.1. Players may use official Riftbound cards of any language as long as their deck contents match the following:
420.1.a. All cards within the same deck or subset that can be shuffled together or drawn from randomly must be the same language. For example:
420.1.a.1. All cards in a player’s Main Deck and sideboard must be the same language as each other. Your Chosen Champion is a Main Deck card.
420.1.a.2. All cards in a player’s Rune Deck must be the same language as each other.
420.1.a.3. A player’s Legend can be a different language than their Main Deck or Rune Deck.
420.1.a.4. A player’s battlefields can be a different language than their Main Deck or Rune Deck.