"Sibyls..." Clow looked thoughtful - and curious. "From what I've gleaned, your world isn't a different Earth, but at the same time - in my world, that word has very ancient roots, and refers to female prophetesses in legend. Aces can be the highest or the lowest card in card games, though that property doesn't have much relevance in divination."

He settled back in his chair a little. "Perhaps... for your world, they were created outright as a means of divination. In mine, they were simply playing-cards first, but the symbology of the trumps drew people interested in using it for magical purposes as well. A great deal of magic is, after all, the symbols we use for it."