"Samurai Warriors: Xtreme Legends is a PS2 expansion disc for Samurai Warriors . While Xtreme Legends can be played alone, it is not possible to use any of the features of the original.
This offers four new characters (Imagawa Yoshimoto, Hashiba Hideyoshi, Honda Tadakatsu and Inahime) and a brand new mission and map. This also offers new weapons, a new survival mode, and fixes several problems."
Source: Wikipedia, Samurai Warriors, available under the CC-BY-SA License.