Kai

Kai 1st appeared in Samurai Wariors 3.

Samurai Warriors
In Samurai Warriors 3, Kaihime starts as a fresh recruit for the Hōjō army. Her first battle is at Tonegawa against the Uesugi. After the conflict, the battles in Kantō momentarily subside and Shingen Takeda passes away. Soon after Nobunaga's death, Tokugawa and Sanada troops invade Shinpu Castle. As they fight, Kaihime begins to grasp what it means to protect those important to her and swears to better serve her master, Ujiyasu Hojo. Hideyoshi Toyotomi eventually becomes the land's most influential ruler and heavily surrounds Oshi Castle after Masamune Date's surrender. Although the odds are against them, Kaihime fights to inspire the men and breaks the water gate. While she knows that the battle is still against them with Masamune's reinforcements, Kaihime defends the Hōjō until the conflict ends. Upon their victory, however, Ujiyasu passes away and entrusts her to continue protecting the Hōjō family. Odawara Castle falls with Ujiyasu's death and they surrender to the Toyotomi. When Masamune riots against Hideyoshi in the Kasai-Osaki riot, she decides to uphold Ujiyasu's final wishes and joins the subjugation effort. By this time, Kaihime believes that she is fighting for a more valuable dream for her lord and won't tolerate Masamune's ambitions. After Mitsunari perishes, the Toyotomi family is in danger so she joins Yukimura's desperate resistance at Osaka Castle to continue protecting her dream. Before the battle, she spots a depressed Kunoichi trying to leave Yukimura and encourages the shinobi to return to her master. Together, they successfully save Yukimura and the struggling Toyotomi army, claiming victory against the Date and Tokugawa forces. With her dreams fulfilled, she enjoys her life as a normal woman in the new land of peace. She and Kunoichi humorously try to pick out new clothes and join the court women in fawning over Muneshige (and scoff at the accompanying Ginchiyo).

History
Kaihime was Narita Ujinaga's eldest daughter and a maiden said to be of unparalleled grace and beauty. To appease her father, who lamented only having daughters as his heirs, she also possessed bravery and cunning that was unlike other princesses. She was said to have had two sisters, Makihime and Atsushihime. She spent the majority of her youth at Oshi Castle. She was married to Yura Narishige until his death in 1578. In 1590, during Hideyoshi's siege of Odawara Castle, the Toyotomi army surrounded the nearby Oshi Castle with 3,000 men. There were only 300 men fortifying the castle's defenses and Kaihime's seventy-one year old grandmother (and mother in some accounts) was said to have taken charge of the strategic planning of the castle's defense. The defenders successfully remained resilient to the invaders' attacks, mainly due to the marshlands and steep ditches that surrounded the castle. In June, Mitsunari Ishida marched with 20,000 men in an attempt to take the fortification. He ordered the castle to be burned down but, due to the moist enviornment and high morale of the defending army, it was nearly impossible to start a blaze. Opting for a frontal assault, Mitsunari marched his men through the banks near Takamatsu Castle. The Narita vassals saw their opening and broke the river's dam, greatly demolishing Mitsunari's numbers. The fleeing soldiers were chased by Narita vassals. Kaihime was said to have volunteered to rout the remaining soldiers, donning armor and riding on horseback with 200 men. Masayuki Sanada, Yukimura Sanada, and Nagamasa Asano came to Mitsunari's rescue. She met with Sanada's reinforcements in combat and slayed their vassal, Miyage Takashige, in battle, taking his head as her trophy. Her accomplishments gave a huge boost to ally morale and forced Mitsunari to surrender, reporting his failure to Hideyoshi. Mitsunari was greatly ridiculed for failing to capture a position "guarded by a woman". To this day, the long strait where the incident occurred is also known as the "Ishida Tsutsumi".When Odawara Castle surrendered, her father also chose to do the same with hope to end warfare. When her family exited the castle, Kaihime exhibited an air of dignity. Hideyoshi generously forgave them and allowed them to keep their properties. A few rumors say that this was due to Kaihime's elegance. After their surrender, Kaihime and her father were entrusted to Gamō Ujisato and lived in Iwashiro-fukui Castle. Sometime when her father was away, an internal rebellion was caused by Hamada Shugen and his younger brother. During this time, her mother-in-law (or mother in other sources) was killed. As soon as she heard about the incident, Kaihime sought to end the rebels. After hiding her beloved sword, Nagiri, under her robes, she feigned a jovial conversation with her parent's killer and waited for them to lower their guard. When she saw her chance, she slayed the instigator and two followers, effectively repressing the bloodshed. Since her time at Iwashiro-fukui Castle was relatively short, some people argue that this could have occurred at her family home instead. Hideyoshi heard of her bravery and took a great liking towards her. He donned her one of his concubines, awarding her family with 20,000 koku and more territory as a result. Her fate from here is largely unknown though it is said that she saved Senhime during the Osaka Campaign and retreated to live as a nun. Others say that she either committed suicide or was slain before or during the conflict. Another story says that when the castle fell, she fled with Oiwa no Kata (Narita Goheisukenao's daughter) and Nahime (Oiwa no Kata's eldest daughter) and the three of them became nuns at Tōkei-ji. Another story says that when they were retreating, Kaihime personally defended Nāhime from assassins. Some speculate that this was because the girl was actually her and Hideyori's child.