Jason is correct. The Rulebook says that some effects are summarized on the cards and explained in detail in the Rulebook. Effects like the movement and attack of the Dead Men and the Ents are complex enough that they can't be fully explained in the space available on a card. However, once you understand those rules, the cards become enough to remind you of them.
This point seems worth emphasising as it's a bit of a departure from how things have worked to this point - usually card text trumps the rules in the book. It seems in the case of faction cards allowing movement and attacking, if the card and rules don't agree exactly (or there's room for interpretation) we should go by the rules rather than taking the cards literally.