hey remembers roxas after to log off but got an idea. In 368/2 days it says when zexion attacked xion for he saw her an ven for a second giving her the advantage to fight back. Since xion fis a replica of sora and his memories that means that he's seem ven or ven maybe became a part of sora meaning that a nobody can proably also be created from the memories of there pastselves making it why ven looks so much like roxas. just a guess.