"Sign in Blood" is a sorcery card from the Magic: The Gathering Archenemy set, classified as an Unknown rarity. It allows players to draw two cards and lose two life, making it a strategic choice for decks that can afford the life cost. Currently valued at $0.74, it appeals to collectors and players alike for its utility and thematic relevance within the game's lore. Market data shows steady interest, reflecting its role in various competitive formats.