An interesting reveal is the fact that Shiori had given Hinako mermaid blood. Though an interesting aspect of it is that it happened when the family went on their trip, but before they had the accident. She mentions a debt to repay; what does that mean?
Much like Miko we see monsters lie to their benefit. Though in the case of Miko it was more understandable for her lies because she was Hinako’s best friend. Though Shiori promised Hinako a death, in reality that was the lie. Essentially their whole relationship is a lie at this point. Though the mermaid blood coinsigning with it was the mermaid blood that allowed Hinako to live. Though curious, Shiori does claim she lived a lot like Miko once. Curious what changed her.
There is also the angle of Ayame with Hinako calling her mom. Is there a potential connection between her and Hinako’s family? Though she suffered a loss when she was human with the death of her stepson. It is a reminder that death is permanent.