The significance of the Sengoku Jidai in Japan, also known as The Warring States Period, is that it was a period of chaos amid a disputed succession of rulers following the Ashikaga Shogunate. Even though no one won this war of succession, what followed was a century and a half (15th to the end of the 16th century) in which men of great talent would fight for control of different regions, sparking many famous tales and legends that continue to be represented in popular culture the world over.
The three most famous leaders (among others) are Nobunga Oda, Toyotomi Hideyoshi, and Tokugawa Ieyasu. Oda is well known for his demon-like power and military strategies that had wiped out the Iga clan of ninjas and dominated the battlefields of Okehazama.
Hideyoshi was a close ally of Oda who took over and expanded territory following Oda's betrayal and death at Honno-ji by Mitsuhide Akechi. He quickly defeated Akechi , ultimately being the first to unify all of Japan since the Onin War that had led to the Jidai.
Tokugawa Ieyasu was a cautious yet bold leader, known to remember his enemies. Unlike Hideyoshi who had wanted to conquer land beyond Japan, Ieyasu just wanted to bring order and end the war consuming his homeland. Being the ultimate victor by bringing an end to the civil war ushered in the Tokugawa Shogunate. This would bring stability and relative peace to Japan for hundreds of years to come, until the time of the Mejii Restoration of 1868.