Dynasty Warriors producer Akihiro Suzuki announced a demo for Dynasty Warriors 8: Empires will be available in Japan on October 8. If you have a Japan region PSN account you can get the Edit Mode demo for PlayStation 3 and/or PlayStation 4.
An Xbox One demo is also in the works and is planned to come out at a later date.
Dynasty Warriors 8: Empires comes out on November 20 in Japan. A Western release is slated for Q1 2015.