[Steve_OS]

According to the UFC 2010 Undisputed community site, the demo will feature Rua, Machida, Evans and Jackson.

Quote:

"The demo will feature the following 4 Light Heavyweight Fighters: * Mauricio "Shogun" Rua * Lyoto "The Dragon" Machida * Rashad "Sugar" Evans * Quinton "Rampage" Jackson In this demo, you'll be able to jump right into Exhibition Mode or challenge your friends offline with Tournament Mode. More details on these modes coming soon. A release date hasn't been set, but we'd like to release the demo a full month before Undisputed 2010 hits store shelves on both PSN and Xbox Live. Stay tuned for more info."