Fall of the Samurai is a great big standalone expansion for Total War: Shogun 2 that will pit the samurai classes against imperial forces that threaten the power of the Shogunate. The influx of colonial forces and new technology leads to an internal struggle between pro-imperial forces and traditionalists. The result? WAR! Katanas will meet muskets on the battlefields of Japan.
There will be six new factions to play with, 39 new land units, 10 new naval units, an expanded campaign map, three new agents, port sieges and new technology, including railways. It's available to pre-order now on Steam and the SEGA store for £24.99 / $29.99
Pre-ordering on Steam will grant you the Tsu faction, described as astute strategists and master ninjas. The SEGA store pre-order comes with the Obama faction, who have nothing to do with the incumbent US administration. They're described as an authoritarian people "who are unsurpassed in controlling people and trade."
The official Total War: Shogun 2 - Fall of the Samurai pre-order page also lists a limited edition as "coming soon." That'll contain the Saga faction, who can quickly adopt the fresh technology brought into Japan by Imperial forces. Fall of the Samurai is due out in March.