Short answers, pulled from the story.
The word "samurai" is thought to come from "saburau," meaning "one who serves their lord." Samurai were defined as retainers or vassals. The warlords who ruled Japan, the daimyo and the shogun, were members of the bushi class but were not referred to as samurai.
The institutional basis of samurai status was dismantled after the Meiji Restoration of the late 1860s through a series of reforms, including the reorganization of samurai lords as kazoku in 1869, the abolition of domains in 1871, and the introduction of conscription in 1873. The status category of shizoku remained in official use until 1947.
Swordsmanship, archery, and horsemanship were the primary martial skills of samurai. During the Heian period, the tachi and naginata were closely associated with the warrior class. By the Sengoku period, the shorter katana and the yari had become dominant battlefield weapons alongside the tanegashima matchlock musket, which Portuguese explorers introduced in 1543.
The Satsuma Rebellion of 1877, led by Saigo Takamori, was the largest and last major armed revolt by former samurai. Its defeat confirmed the military and political authority of the Meiji central government and marked the end of large-scale armed resistance by disaffected shizoku.
Many women of the samurai class were trained in wielding a naginata or a small knife called the kaiken, in an art called tantojutsu. This training prepared them to defend their households when warrior husbands were traveling or engaged in battle. Some women also actively participated in battles alongside male samurai, though most were not formal samurai.
Yamada Nagamasa was originally a palanquin bearer from the lowest end of the samurai class who traveled to Southeast Asia after the Battle of Sekigahara. He rose to prominence in the Ayutthaya Kingdom, in what is now southern Thailand, and became governor of the Nakhon Si Thammarat Kingdom. He is considered the most famous Japanese samurai mercenary to have served abroad.