Momoyo's grandfather and master.
Momoyo's teacher under Tesshin.
Kazuko is Momoyo's adopted sister. Kazuko admires Momoyo and wishes to help as in the Kawakami Temple as an Assistant Master.
Since her fighting style is very similar to his, and him being the previous assistant master alongside Lu Yi, Momoyo addresses Shakadou in a respected tone to him. Although already exiled, it is suggested that Shakadou personally taught her his techniques when she was still a child and before his exile from the Kawakami Temple. It's stated by Lu that Shakadou is the reason why Momoyo is the way she is and the very reason why Lu wants to make sure Kazuko doesn't become like Momoyo.
As the oldest member of the Kazama Family, Momoyo is seen as the older sister of the group. She gets challenged on almost a daily basis by fighters around the world and even students from other schools who seek recognition and fame. However, she effortlessly defeats them all, to the point in which she gets frustrated. She takes out all her frustration on Yamato by teasing him.
Momoyo has an older sister-underling relationship with Yamato. As such, she'll occasionally pick on him, but will also go out of her way to look out for him. In the final few episodes she admits that she loves him.