When the Portuguese first landed upon Japan's shores in 1543, they stroked their handlebar mustaches and said, "You know, that whole honorable swordsman thing is working well for you, but what you really need is our brand of GUNshido." They then shot the word "PORTUGAL" into the side of the Emperor's palace. My history recollection is probably incredibly inaccurate by now, but still, guns remain the central theme for the November 30 release of the Otomo Clan DLC for Total War: Shogun 2. You'll get a new playable faction with five armed unit types, extra buildings, and special traits.
The Otomo Clan high-fived Portugal's trade deals early on during Japan's feudal fracas, and it nabs a number of assets following the basic military doctrine of "take anything and add a gun to it." The Otomo Donderbuss Cavalry, for example, masters the art of firing the shotgun-like Donderbuss rifle on horseback. The Otomo Matchlock Samurai combines fearsome swordsmanship with rifle-fire volleys range, because handing samurai another method of dealing swift death is both overkill and freaking awesome .
The Portuguese Tercos (which I read as "Portuguese Tacos" at first glance) and Otomo Matchlock Ashigaru supplement the samurai as long-range riflemen. On sea, the Otomo Matchlock Kobaya harnesses "Christian fervor" for more accurate shots during marine operations. I guess I missed the Bible passage granting dead-eye divinity.
Cash-strapped warlords can also lease off a single building slot per city to the Portuguese for a lump payment burst of funds towards rapid troop buildup. As for traits, the Otomo Clan provides appropriate bonuses to pumping out the firepower:
Steam is offering a 10 percent discount on pre-purchases, so head over to the DLC's store page for more info.