WARNING: The following contains spoilers for Episode 31 of Yashahime: Princess Half-Demon, "Takechiyo's Request," now streaming on Crunchyroll, Funimation, Animelab, and Hulu.
As the half-demon twins gear up to save their mother Rin, they're both forced to face their weaknesses and limitations in Episode 31 of Yashahime. While on their mission to slay rock demons, Kohaku and Hisui surprise the twins and join them out in the field. During the encounter, Kohaku warns that Towa's unwavering strength and determination are actually life-threatening weaknesses.
When Towa and Setsuna team up to slay rock demons to protect a human village, the twins play music together while they wait for the demons to show themselves. Setsuna continues to play her mother's song on her violin when she's finally joined by Towa and the new flute she got from Rion. The rock demons show up hoping to take down Sesshōmaru's daughters and earn respect among their fellow demons. When it appears they've defeated the rock demons, Towa lets her guard down and asks them to surrender, which gives them a chance to attack her again.
Given Towa's time in the modern era, her sheltered upbringing has fostered an arrogance and naivety that has put her life in danger several times throughout the series. Early in Season 1, Setsuna and Moroha warn Towa not to underestimate the feudal era and emphasized that demons are ruthless beings who won't hesitate to kill. While Towa has improved her combat skills and survival instincts since arriving in the feudal era, it's clear she still lacks the resolve to kill the enemies coming for her life.
Upon noticing that Towa's still too kind and innocent for this era, Setsuna suggests that Towa return to her world while she saves their mother on her own. Towa wonders whether this suggestion is because Setsuna hates her, but Setsuna is actually upset with herself because she believes Riku was right about her not being strong enough to protect Towa in this era.
In the middle of their mission, the half-demon twins are unexpectedly visited by Kohaku and Hisui on behalf of the Demon Slayers. Hisui catches Towa off guard when he suddenly throws his Hiraikotsu at her from behind, forcing her to instinctively dodge it. Hisui admits that he was testing her because his uncle told him that Towa doesn't know when to back down or run away. When Towa claims she actually ran away from Hirakotsu just now, Kohaku points out that she merely dodged and left herself open to attack when she should've fled.
While Hisui talks to Setsuna about how to build trust with her weapon to save her mother, Kohaku tests Towa to expose her greatest weakness. When Kohaku provokes Towa, she recklessly attacks him head-on, without hesitation. As his weapon comes down, he specifically warns Towa to dodge it, but she stands her ground and counters with her own weapon instead. Since she once again refused to run, Kohaku is able to target a fatal spot on Towa's body.
Kohaku accuses Towa of refusing to dodge when it's necessary because she doesn't see it as an option, speculating that something from her past is causing her to feel too ashamed to run away. While he admits that Sesshōmaru and Kikyo are the only two people he's met who never run, Kohaku warns that this behavior is reckless and deadly for Towa and expresses great concern for her safety.
After Kohaku assures Towa that it's okay to run away, there's still the lingering question of why she refuses to run in the first place. This behavior may come from the regret and shame she feels for fleeing the forest fire and letting go of Setsuna's hand as a child, which ultimately separated the sisters for years. As the series progresses, Towa will have to overcome this dangerous weakness and learn when to run away from a fight she cannot win.
