My understanding is that all the cards came through from Miyu's universe. The disruption they caused in the magic field matched the one that was traced back to that cavern where, as far as we can tell, the initial breach between worlds occurred. The place that Miyu emerged from without first having entered. And more, Caren told us the cards appeared at the same time Miyu emerged from the cavern. That seems a clear indicator that, intentionally or unintentionally, when Miyu crossed over into Illya's world, she brought the cards with her.
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