So um, what did this Riku guy do to her to make her "unhighed" like that? Feel like I'm missing a whole chapter to get the explanation lol.
Pretty sure this is still part of the mystery. But the story looks like it's going in the direction of him attacking her insecurities. Sadly, there are lots of stories like this irl, where a partner makes a girl feel like she isn't pretty or smart enough, but the same partner will insist that he accepts her anyway, creating an unhealthy dependency on his validation. We can already see Mao was never as confident as she seemed, the mean comments on her music really got to her, and she's not the prettiest girl in the room, so she already had a lot of insecurities ripe for exploitation.