Your deck may only contain 3 total Signature cards that have the same Champion tag as your Champion Legend. 1. Regardless of name, a deck may only contain a sum total of 3 Signature cards. 2. All of the Signature cards must have the Champion tag that corresponds to the Champion Legend of the deck. 3. Signature cards are not Champion units and cannot be placed in the Champion Zone.
§ 103.2.d Core Rules PDF (officieel)
§ 103 To play Riftbound, a player must have a Main Deck, a Rune Deck, a Champion Legend, and a number of Battlefields determined by the Mode of Play. These are collectively referred to as a player’s deck.
§ 103.2 A Main Deck of at least 40 cards: A Chosen Champion Unit, as well as Units, Gear, and Spells
