Since Roxas came as a "new" member of the Organization XIII, and Aqua has turned the Land of Departure into Castle Oblivion, and Xehanort is crazy about Ventus, and Xemnas became Ansem's apprentice since the end of Kingdom Hearts Birth by Sleep, and in a Kingdom Hearts Dream Drop Distance cutscene, "Ansem"(I think it's Young Xehanort) made Nobodies out of them, So maybe 1 year after Kingdom Hearts Birth by Sleep? I could be wrong... >W<