How do you get lu bu in samurai warriors 2 empires?

Lu Bu is not available to play in Samurai Warriors 2 outside of modding. There's a historical and cultural reason for this as Lu Bu was a historical character from the Three Kingdoms. Three Kingdoms is a tripartite of 200s AD China involving three warring kingdoms. Samurai Warriors is based in the Warring States from years 1467-1573 period of Japan. The Japanese and Chinese see it as an insult to mix their cultures especially iconic elements due to their violent history with each other. So officially putting Lu Bu in Samurai Warriors would have been seen as an insult by the Chinese and Japanese. In addition to the above Lu Bu will have been long dead by the time period of Samurai Warriors.