Seiga Kaku is a hermit in the service of Gensokyo’s Taoist faction. Back when she was a regular human, presumably living in China, her father left her family to become a Taoist hermit, opening Seiga’s own interest in Taoist philosophy. She never got the chance to explore this fascination, however, as she married into the wealthy Kaku family. Her reason for accepting this marriage is unclear, but she was dissatisfied with her life despite the tremendous degree of freedom her new family offered her (at least by the standards of 5th Century China, which is a number we can roughly infer through her later interactions with the semi-historical Prince Shotoku). Of course, becoming a Taoist hermit necessitated abandoning her in-laws and other social connections so her interest in Taoism was the one thing married life couldn’t afford her.