The following details are from an official Koei Tecmo press release:

Celebrating the series’ 30th anniversary and marking its return to the west after an eight-year hiatus, Romance of the Three Kingdoms XIII tells the tale of a collapsing dynasty and the emergence of power-hungry factions, setting the scene for a complex chessboard on which players can follow and influence the fateful events leading to the unification of 2nd century China. Blending deeply strategic gameplay with historically-accurate warfare, players can climb the proverbial leadership ladder as one of 700 historical characters during a turbulent era of political instability, large-scale conflict, and human drama.