Nō

Is Saitou Dousan's daughter, otherwise known as Kichou.

Background
Not much is known about her other than the fact that she is the daughter of Saitou Dousan.

Arrival in the Sengoku Period Arc
When Saitou Dousan agrees to his alliance with Nobuna, he sends his daughter to her as per the arrangement. when she arrives, her servant informs Nobuna not to send reinforcements for her father who is currently being attacked by her brother's army and soon to be defeated.

Trivia

 * She is based on the historic figure of the same name and unlike most characters in the series she has not been gender-flipped, however rather than becoming Nobunaga's wife, she ended up becoming Nobuna's sister instead.