Sōhei

"Benkei stood there defiantly, naginata in hand, and so terrible did he look that none dared approach him."

- Stephen Turnbull, The Samurai: A Military History

Warrior monks had existed in Japan since the end of the Japanese classical age. At first, they simply existed to fight other monks; much of religion was politics, so when two monestaries had a feud, often violence would break out. For over two hundred years, the Sohei merely existed to fight each other in small temple conflicts.

All this changed when the Genpei war, one of the many great civil wars of Japan, began. The two warring clans, the Minamoto and the Taira, wished to bulster their samurai forces, and appealed to the now many warrior monestaries. Both sides obtained help from various groups, and their skill in battle was famous.

After the Genpei war, the monks went back to rebuilding their monestaries, and didn't really participate in the wars of the next couple hundred years, once again only fighting each other. The Onin war started in 1467, localized in Kyoto, where many monestaries were, so much of the Sohei could no longer be passive. This conflict grew into a nation-wide civil war, now known as the Sengoku Jidai.

Meanwhile, in the countryside, a new face of the warrior monks arose; the Ikko Ikki. These religious fanatics believed in the downfall of the Feudal system, and led a peasant rebellion against the Samurai rulers. Many of the daimyo lords, including Tokugawa Ieyasu, future founder of the Tokugawa Shogunate, sent armies to fight the rebels. The Ikko Ikki took began to spread, conquering more land, but eventually, in 1580, they were defeated.

While the next twenty years saw more warrior monks siding with various forces, when Japan was unified under Tokugawa, the time of the warrior monk ended.