Also known as: Kuranosuke—nickname (内蔵助)
Titles: Mutsu no Kami, Ecchuu no Kami, Chamberlain
A daimyo of the Sengoku, born in Owari. His father was Sassa Morimasa. His two older brothers, Sassa Masatsugu and Sassa Magosuke, died in battle, so Narimasa became head of the clan and master of Hira Castle in 1560. He distinguished himself in the loyal service of Oda Nobunaga and fought in many of Nobunaga's battles. His name was first on a list for the Kurohoro-gumi, an elite group of Nobunaga's bodyguards.
In 1580, he backed Jinbou Nagazumi against both the Uesugi Clan and the Ikkou-ikki in Ecchuu, and was given half the province. The following year, he was named governor (Kami) of the entire province when Jinbou Nagazumi lost his standing. He made Toyama Castle his main castle and performed extensive repairs and renovations on it.
After Nobunaga's death in 1582, Narimasa continued to engage in fierce battles with Uesugi Kagekatsu. He took the side of Tokugawa Ieyasu and Oda Nobukatsu against Toyotomi Hideyoshi, but later surrendered to him in 1585 when Hideyoshi laid siege to Toyama Castle with 10,000 troops. He lost Ecchuu, but was given a fief in Higo in 1587 for merits in the suppression of Kyuushuu, along with instructions on refraining from hasty reforms. Ignoring those instructions because of illness or perhaps misunderstanding, Narimasa immediately set out on Hideyoshi's nationwide land survey, resulting in rebellion of the province. He was charged with misgovernment and committed ritual suicide.
He wrote the following as his death-poem: "The shell of my begging bowl in which I have placed the evil delusions of these recent days now breaks" (この頃の 厄妄想を 入れ置きし 鉄鉢袋 今破るなり).
Narimasa is said to have brutally killed his concubine, Sayuri, along with her family for a rumor of infidelity. The legend goes that Sayuri cursed him before she died, and the curse was responsible for his death at the hand of Toyotomi Hideyoshi.
In Mirage of Blaze: He is kanshousha who has entered the «Yami-Sengoku» as one of the Oda's commanders, described as a tanned, fearless-looking young man, a "mountain cat in human skin." He and Mori Ranmaru don't appear to be on the best of terms. He later seeks his death at Sayuri's hands in remorse for the way he brutally tortured and killed her in their previous lives.