Doma, which is no doubt modeled after China, is hinted to have a regressive, sexist culture of oppression against women. This is exacerbated by imperialist conquest by the Garleans. Yotsuyu's story touches on the pain of conflicting identities, family abuse, and redemption, but it also serves as a sociological critique of Chinese, Korean, and Japanese culture.
The most obvious thread of this critique is seen through the lyrics of Tsukuyomi's boss theme. The part sang by the men represents not just the oppression by people in Yotsuyu's life, but also the oppression by imperialist Westerners.
'The vanity of the west flows into the east.'
'Worthless daughter, you shall step into the darkness of the night.'
'Restless though those eyes may be, they cannot see how far the self has fallen.'
'Powerless dew, you cannot help but obey the tides.'
Although at first glance we might be tempted to conclude that this is merely the POV of Yotsuyu's family (Asahi and her parents etc.), that is an incomplete analysis of these lyrics. Note that these lyrics are sung in English, contrasting the rest of the song, which is sung in Japanese. In colonial history, the oppression of women was often not merely the product of the local culture, but also the product of Western imperialist oppression. Yotsuyu's oppression was an intersectional one, where the forces of Western imperialism and sexism doubly oppresses and abuses her until she became completely beyond redemption. Furthermore, describing Yotsuyu as a 'powerless dew' that can only 'obey the tides' has a double meaning here. One is her lack of self-agency as her parents sold her to slavery. The other is her lack of self-agency under a Western empire colonizing Doma. Even while she was a viceroy, she still had no choice but to listen to Zenos and was indirectly puppeteered by him.
'As I don this florid gown,'
'Purpose, torn and cast aside,'
'Fate to be foiled, chains to be broken, life to be scattered in'
'the wind'
Yotsuyu's inner monologue is sung in Japanese, and contains many symbols of fragility and ephemeralness. She is symbolized as a flower, beautiful but fragile, and plucked away by people for their own selfish enjoyment. This is much like how women were treated in East Asian culture up until the 20th century. They were seen as mere objects of beauty, to be used and ab-used. They were seen as fragile, just like the flower. And they did not have agency, just as flower petals fly in the wind. The oppression of women in East Asia led to many barbaric acts, like foot-binding, whose only purpose was to make the female more beautiful for the male gaze. Yotsuyu's obsession towards beautiful dresses and make up serves a similar purpose. As a woman, much of her worth is derived from her beauty. In the story we almost see no other positive aspects of her before she lost her memory.
Finally, the character design of Yotsuyu also directly relates to the Opium Wars. The subjugation of China through the opium wars led many to become addicted to opium, and it became a symbol of decadence in China and Korea. Yotsuyu's smoking is once again a reminder at her decadent nature, but it also hints at the source of it: imperialist conquest. It also evokes East Asian feminist literature, such as The Golden Cangue, where a matriarch, who was abused by her parents and forced to marry a paraleiptic against her will, reproduced her abuse towards her children. In that novella, she was also an opium addict and even forced to her children to get addicted to opium like her. Just like Yotsuyu, her addiction to opium and her smoking hints at her addiction to abuse and her reenactment of oppression towards others. She was forced to suffer abuse by imperialism and misogyny, but now she reproduces those abuses because she is addicted to it. She does not even have a choice anymore. The same goes for Yotsuyu.
Yotsuyu's story is simply a brilliant portrayal of the consequences wrought by imperialism and female oppression. It becomes generational, which is why it is so hard to get rid of misogyny even today. I hope to see more stories like this from Square Enix, powerfully critiquing problematic sources of oppression, such as the one in Yotsuyu's story.