Gekokujo is a mod for Mount and Blade Warband set in the Sengoku period of Japan. The name is a term often translated as "the low-ranked taking over from the high" and was chosen because it was a running theme during that era: from the illustrious Ouchi clan--a belligerent party in the Onin war--being displaced by the Mori (their vassals); to the rise of Toyotomi Hideyoshi (who began his career as a cook and sandal bearer); to the beginning of the Tokugawa shogunate itself (Ieyasu was an upstart who probably fabricated a claim of descent from the Minamoto clan--the only ones allowed to be granted the title of Shogun in the first place). As a player of Gekokujo, you will start from nothing and attempt to gain control of the entire country, making the title even more fitting.
This is the full 2.1a version of the mod as a rar file, as an alternative to the installer. Don't get this unless you know what you're doing. Extract to your /modules/ directory