Xia Jinyuan was unfazed, even if Elder Fu came over to visit Grandpa, that doesn’t matter, since the girl he had always wanted to bring home to meet his grandparents was here. However… it was slightly regrettable. “Actually, I hoped that I was the one who brought you home; that way, it’ll seem more formal.” Walking past the shade, Xia ...

This is going to be awkward for her already near nonexistent social life.
Wow, must be pretty annoying being a Naiad, 16 hours. You are pretty much stuck. Also, doesn’t that mean that Tiana’s mother isn’t full Fairy as well? Wasn’t it also mentioned that children of male Fairies end up becoming the mothers species only with fairiy blood? Did I overlook an exception rule? But regarding Tiana’s mother, she as well doesn’t have it easy with the water aspect. Days aren’t that long, so two to four hours of bathing every day limit your day to day live pretty hard as well. She would not be able to go on longer expeditions and become an adventurer, if she ever fancied it. If I were her I would just sleep in the bathtub. This way you don’t lose as much precious day time. Since she seemingly doesn’t need to breath underwater this looks like a viable option. If the mother isn’t a full fairy Tiana isn’t even a half one but rather quarter with a quarter Naiad but oh well.
“If I rewrite Substitute Hero for print publication, I’m definitely putting the info about Tiana’s grandmother in earlier. While I was writing a scene a number of chapters further on where it became important, I realized I had never mentioned this detail before.” If I can make a suggestion, you should write about the “skin condition” in the part about her return home after being expelled from the party, then the whole explanation about her mother and the baths when she takes her first bath after returning home. I feel that doing it that way will make it smooth and part of the tale. Currently, it still has that feeling of something dropped from high, without any foreshadowing. The whole thing about being starved for specific mana becomes important from now onward, so foreshadowing is important (I have returned back after reading several of the following chapters to comment). Thanks for your work, it is a nice tale.
Heyyy finally caught up. Anyways I can just FEEL the annoying misunderstandings. Especially if it’s our friendly heroine or one of the bullies.