Sin 七つの大罪 X-TASY is a mobile game adaptation of the anime series "sin 七つの大罪". The game is free to play and available on the iPhone platform. The game is faithful to the anime series and is set in the world of the seven deadly sins. The storyline is about a fallen angel named Lucifer who becomes the "arrogant demon king" and embarks on a journey with other demon kings to take revenge on the seven demon kings who sealed her power.

The game features original characters created by famous illustrators, in addition to the original characters from the anime series. The game also has high-quality graphics and animations, thanks to the use of Unity 3D and Live2D technologies. The player can collect and admire their favorite characters in the game's "character appreciation mode". The game also features voice actors from the anime series, including Yumi Hara, Houko Kuwashima, and Satomi Arai. The game requires iOS version 10.0 or later and approximately 2GB of storage space.