Falcom is the latest developer to bring one of their franchises to GREE, a social network service designed for mobile phones in Japan. Ys Nexus was announced for the platform and it’s an extension of the Ys universe.
The game is designed as an online MMORPG where players complete missions. You’ll run into various characters from the Ys universe as NPCs. Ys Nexus probably won’t be a "MMO" like Ys Online though. GREE games tend to have a simple interface more a kin to Facebook games. In fact, Square Enix ported two GREE games, a Chocobo themed dungeon crawler and Knights of the Crystal to Facebook.