JRPG developer Gust is working on yet another addition to its Ar Tonelico series exclusively to the PS3. Like its predecessors, Ar Tonelico III will explore a new music-based battle system, with players able to create custom songs and change background music, according to Siliconera. The initial teaser trailer doesn't reveal much -- beyond showing off some of the characters, it reveals a surprising early 2010 Japanese release for the game.Gust's previous PS3 game, Atelier Rorona, was in full 3D, and we're hoping Ar Tonelico III will follow suit. NIS America has localized both PS2 Ar Toenelico games in the past, so it's likely the third game will also find its way to the publisher some time next year.