Square Enix used Facebook to announce a new fantasy card battle role-playing game for iOS devices called Guardian Cross. They plan on releasing it this Spring, and an Android version will follow some time after. They also say that the Knights of the Crystals team created this title.
The price is listed as "free-to-play" on their FB Info page. More info will be released soon, they say.
I freakin' love card games, and from the screenshots it looks super nerdy.