Pokémon Black & White take place in Isshu, a region situated far from the ones we’ve seen in past Pokémon games. At the centre of Isshu is Hiun City. “Hiun” means “ill fate” or “misfortune.” It can also refer to clouds flying through the sky. No doubt the name refers, in some way, to the plot and events that will surround the city.
The first of the previously-announced Pokémon from Gen-5, Zorua and Zoroark, have an ability named “Illusion.” When either of them enter battle, the Illusion ability makes them look like another Pokémon — even the name displayed onscreen — to fool the opponent. The catch is that their element type (Dark) remains the same, which is what you’ll need to look out for.