Honnō-ji incident

The Honnō-ji incident was a conflict between the forces of Oda Nobunaga and those belonging to his vassal Akechi Mitsuhide at the temple of. The event saw the assassination of Nobunaga at the hands of the Assassin Yamauchi Taka, who seized the opportunity to take his Sword of Eden on behalf of the Brotherhood, and delivered it to Liu Yan for transportation to China.

Nobunaga's death saw the rise of his vassal Toyotomi Hideyoshi, who continued his lord's quest to unify Japan under his rule. Secretly, the Assassins helped pave the way for Tokugawa Ieyasu to eventually conquer the land for himself.

Reference

 * Assassin's Creed: Memories