Cesium is a cancelled action adventure that was in development for the original Xbox by FASA Studio / Microsoft Games Studios in 2004. The project was canned in early prototype form and only some concept arts remain to preserve its existence. The game’s world evolved from fantasy floating cities to iconic asian levels and even the main protagonist was probably still undecided. We can speculate that the Cesium project was canned to move their resources on other games, as Crimson Skies. FASA Studio was officially shutdown in 2007.
Thanks to Yulle for the contribution!