It was not long ago since Leaf's popular RPG/Visual Novel, Tears to Tiara, was adapted into anime and manga. It's popularity continues to rise and Leaf finally decides to make a Gaiden (side-story) for this game, with a subtitle of "Avalon's Mysteries."
At the moment there are not much information available as they have just put up the website, but one can already see that all the original characters will appear, along side with a secret character that has yet to be revealed.
The game is announced to be released on 9/17/09 and it will fall under the Adventure RPG genre, exclusively for the PS3.
Tears to Tiara is a game revolved around Arawn, a demon lord released by a priestess of a nomadic tribe. He eventually became the leader of the tribe and leads the tribe to its path of conquest.