Players may use a unique sleeve or additional layer to distinguish their Chosen Champion during game setup, but must change its sleeve to match their Main Deck if it would enter a zone whose information level is private during gameplay. See CR
§ 422.2.b Tournament Rules PDF (officieel)
§ 422 Sleeves
§ 422.2 If a player chooses to do this, all such sleeves must be identical and all cards in a deck must be placed in sleeves in the same manner. Cards in decks must have the same number of layers and be the same orientation at all times.
