9. Date Masamune
Known for his affinity for violence and lack of mercy, Date Masamune was one of the most feared warriors of his era. Having lost the sight in his right eye in childhood due to smallpox, he had to make extra effort to be recognised as a fighter. After a series of defeats in early days, he slowly built his reputation and became one of the most efficient warriors of the time. When his father was kidnapped by the enemies of his clan, Masamune retaliated with slaughtering all of them, killing his father during the mission. He later served Toyotomi Hideyoshi and Tokugawa Ieyasu, as the head of Date clan.