Samurai
The samurai were the military nobility of Japan. They were equivalent to the vassals of European Feudalism.
The Samurai were simply soldiers no different from those in Europe, prior to the Tokugawa dynasty (16th Century). After the unification of Japan, they became a class of warrior-scholars, who developed a code of honor and chivalry which was never tested until World War 2. The mythology they created around themselves led to the belief that Samurai never ran from battle, served their masters faithfully even if it meant death, and commited suicide when dishonored. As Japan was largely at peace for 400 years, these myths are largely not founded in fact. Japan's kamikaze pilots killed themselves because they believed the samurai ideal of service until death, and the hope for an honorable death.