Mrs. Spenser is on a bit of a Korean kick, hence The Warrior. It is the story of a Korean ambassador to Ming China, who is expelled with his guards when relations between China and Korea go sour. Somewhere in the deserts of western China, the band is attacked by Mongols. The Mongols let kill the Ming escort, but have no quarrel with the Koreans. The Koreans notice that the Mongols have captured a Ming princess (Ziyi Zhang), and decide to rescue her, to win back the favor of the Chinese.
The ambassador dies quickly, leaving three factions in the Korean group: the general, now down to a handful of men, feeling somewhat in disgrace; the sergeant, a weatherbeaten grizzled veteran, loyal to his men, his nation and his general, in that order; and the ambassador's freed personal slave, a man of strength and honor, even if he is scorned by his countrymen.
This is a beautiful military costume drama, with great battles and individual fights. It is also an interesting personality study - the personality of fighting men. They are fighting for honor and for the beautiful princess (Zhang seems to have cornered the market on princess roles). They may have no hope of succeeding or even living out the battle, but they continue.
If I may be obscure for a moment, this movie reminded me of the works of fantasy/sf writer Glen Cook. He is noted for the realism of the grunts and mercs that he portrays in his epic fantasies like the Black Company series. Since very few of you have read Cook (or seen The Warrior, either), I guess that doesn't tell you much.
Maybe it would be better to compare The Warrior to Kar Wai Wong's Ashes Of Time Redux - the same grand scope and personal detail.