And no, they have nothing to do with MLP. Though the cards do have a nice shade of purple as a border.
From the preview:
Eight-hundred years ago, the Ki-Rin Clan left Rokugan to scout the world for enemies beyond the Emerald Empire. When they returned, they cut a swathe through the Crab Clan’s defense and devastated the Lion. Though they have returned to the fold, reborn as the Unicorn, the Clan still struggles to integrate with the rest of the Emerald Empire. They are viewed as foreigners with strange ways, wandering nomads who fight in unnatural ways with their powerful Meish?d? magic and superior horsemanship skills.
Today, we’re previewing the Unicorn Clan in Legend of the Five Rings: The Card Game, experts in confusing their foes with a bevy of combat tricks and military might.