I'll reply to all these comments.

One, yes, you've seen Chelsea's trump before, but I hope to present it in a different way once it appears.

Two, yes, Yumi has a couple of cards that are more powerful than Dark Magician of Chaos. However, she will not use them for quite a while. One of them she can't use unless she swaps a few cards from her side deck, and the other she simply won't get a chance to use until the time is right.

Three, Ren has a lot of surprises as well. You haven't seen his trump yet, I believe.

Like I said, these kids won't run out of tricks easy. Keep reading, and you'll see them all.