Oda Nobunaga (織田 信長,  Oda Nobunaga (help·info)^?, June 23, 1534 – June 21, 1582) was the initiator of the unification of Japan under the shogunate in the late 16th century, which ruled Japan until the Meiji Restoration in 1868. He was also a major daimyo during the Sengoku period of Japanese history. His opus was continued, completed and finalized by his successors Toyotomi Hideyoshi and Tokugawa Ieyasu. He was the second son of Oda Nobuhide, a deputy shugo (military governor) with land holdings in Owari Province. Nobunaga lived a life of continuous military conquest, eventually conquering a third of Japan before his death in 1582. His successor, Toyotomi Hideyoshi, a loyal Oda supporter, would become the first man to unify all of Japan, and was thus the first ruler of all Japan since the Ōnin War.

Oda Nobunaga was born on June 23, 1534, and was given the childhood name of Kippōshi (吉法師^?). He was the second son of Oda Nobuhide. Through his childhood and early teenage years, he was well known for his bizarre behavior and received the name of Owari no Ōutsuke (尾張の大うつけ^?, The Fool of Owari). With the introduction of firearms into Japan, though, he became known for his fondness of Tanegashima firearms. He was also known to run around with other youths from the area, without any regard to his own rank in society. He is said to be born in Nagoya Castle, although this is subject to debate. It is however certain that he was born in the Owari domain. In 1574 Nobunaga accepted the title of Kuge (or Court Noble), then in 1577 he was given the title of Udaijin (or Minister of the Right), the third highest position in the Imperial court.

Date Masamune (伊達 政宗^?, September 5, 1567 – June 27, 1636) was a regional strongman of Japan's Azuchi-Momoyama period through early Edo period. Heir to a long line of powerful daimyo in the Tōhoku region, he went on to found the modern-day city of Sendai. An outstanding tactician, he was made all the more iconic for his missing eye, and Date was often called dokuganryū (独眼竜), or the "one-eyed dragon".

As a legendary warrior and leader, Masamune is a character in a number of Japanese period dramas. He was played by Ken Watanabe in the popular 1987 NHK series Dokuganryu Masamune.

Date Masamune was the eldest son of Date Terumune, born in Yonezawa Castle (in modern Yamagata Prefecture). At the age of 14 in 1581 Masamune led his first campaign, helping his father fight the Sōma family. In 1584, at the age of 17, Masamune succeeded his father, Terumune, who chose to retire from his position as daimyo. The Date family was founded in the early Kamakura period by Isa Tomomune, who originally came from the Isa district of Hitachi Province (now Ibaraki Prefecture). The family took its name from the Date district (now Fukushima Prefecture) of Mutsu Province, which had been awarded to Isa Tomomune by Minamoto no Yoritomo, the first Kamakura shogun, for his assistance in the Genpei War (1180–85) and in Minamoto no Yoritomo’s struggle for power with his brother, Minamoto no Yoshitsune. Masamune's army was recognized by its black armor and golden headgear.

Sanada Saemon-no-Suke Yukimura (真田 左衛門佐 幸村, Sanada Yukimura^?, 1567–June 3, 1615 (Keichō 20. 5.7)) was a Japanese samurai, second son of the Sengoku period daimyo Sanada Masayuki (1544–1611). His proper name was Sanada Nobushige (真田 信繁), named after Takeda Shingen's younger brother Takeda Nobushige, who was a brave and respected warrior. He and his father were known as excellent military tacticians. Though their army was very small, they won many battles in which they were outnumbered. Sanada Yukimura was called "A Hero who may appear once in a hundred years" and "Crimson Demon of War", and the famed veteran of the invasion of Korea, Shimazu Tadatsune, called him the "Number one warrior in Japan" (日本一の兵^?).

He was the second son of Sanada Masayuki, his elder brother was Sanada Nobuyuki. He was married to Akihime (Chikurinin), a foster-daughter of Ōtani Yoshitsugu. They had two sons, Daisuke (Yukimasa) and Daihachi (Morinobu).

In 1575, the Battle of Nagashino claimed the lives of two of Sanada Masayuki's elder brothers. Masayuki, previously serving Takeda Shingen and Takeda Katsuyori as a retainer, inherited the Sanada clan and left for Ueda Castle. Yukimura also went, taking the Sanada name as well.

Tokugawa Ieyasu (徳川 家康^?, January 31, 1543 – June 1, 1616) was the founder and first shogun of the Tokugawa shogunate of Japan, which ruled from the Battle of Sekigahara in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but remained in power until his death in 1616. His given name is sometimes spelled Iyeyasu, according to the historical pronunciation of we. Ieyasu was posthumously enshrined at Nikkō Tōshō-gū with the name Tōshō Daigongen (東照大権現^?).

Tokugawa Ieyasu was born in Okazaki Castle in Mikawa on the 26th day of the twelfth month of the eleventh year of Tenbun, according to the Japanese calendar. Originally named Matsudaira Takechiyo (松平 竹千代), he was the son of Matsudaira Hirotada (松平 広忠), the daimyo of Mikawa of the Matsudaira clan, and Odainokata (於大の方), the daughter of a neighboring samurai lord Mizuno Tadamasa (水野 忠政). His mother and father were step-siblings. They were just 17 and 15 years old, respectively, when Ieyasu was born. Two years later, Odainokata was sent back to her family and the couple never lived together again. As both husband and wife remarried and both went on to have further children, Ieyasu in the end had 11 half-brothers and sisters.