Demon Blood is a Weiß Schwarz card from The Seven Deadly Sins SDS/SX03-098. Compare listings from Singapore Weiß Schwarz sellers on CardJio, then jio them on WhatsApp.
Reveal the top card of your deck. If that card is a 《Britannia》 character, put it into your hand. (Otherwise, return it to its original place) Choose 1 of your 《Britannia》 characters, and that character gets +2000 power, +1 soul, and the following ability until end of turn. "【AUTO】 At the beginning of your encore step, put the top card of your deck into your waiting room. If that card is a 《Britannia》 character, put this card into your waiting room."