"6" SIX THEROS BEYOND DEATH BOOSTER BOXES FOR PRE-ORDER
The main set contains 254 cards (TBA basic lands, TBA commons, TBA uncommons, TBA rares, TBA mythic rares), and includes randomly inserted premium versions of all cards. Additional cards are found in the set's collector boosters, planeswalker decks and brawl decks. A unique Buy-a-Box promotional card is also considered to be part of the set. Cards with alternate card frames have another card number than the original version. Borderless planeswalkers are numbered #255-TBA, Showcase cards are numbered #TBA-TBA, the Buy-a-Box is #TBA, planeswalker deck cards are numbered #TBA-TBA and extended artwork cards are numbered #TBA-TBA. The Bundle promo is numbered #TBA. Finally there are FNM-treatment cards from the Universal Promo Pack numbered #TBA-TBA. Both regular and foil versions of these cards may be found in the collector boosters.
Theros: Beyond Death introduces the Keyword Action "ESCAPE" spells with escape can be cast from the graveyard for their escape cost. The cost includes exiling a number of other cards from the graveyard. If a creature escapes, it may receive an additional bonus.
Returning mechanics from the Theros block are Constellation and Devotion. "Hero of the Nyxborn" and "Heroes of the Revel" effectively have Heroic, without the actual ability word.