I'm intrigued. Please elaborate on the matter about the language thing
Well, I'm exaggerating a bit, but there is quite a bit of awkwardness resulting from Master's lack of a real name. Usage of "you" is uncommon in Japanese, since usually people just call each other by name when speaking to them, but by necessity Stella and Mist use "you" quite a lot—Master doesn't have a name for them to use, and they can't call her Master since she isn't their master. When Stella is talking about Master indirectly, she uses "kanojo" ("she") which is also uncommon in Japanese—usage of third person pronouns is pretty rare, usually people just call others by name when speaking about them as well. It's not completely out of the ordinary, but it's clear that the characters would probably be calling her by name if she had one.
It'd be too rude/overly familiar for Marie to refer to Master by pronoun, so she calls her "Mel's Master" to her face, or just doesn't use any form of address. This isn't entirely unusually, since people often refer to each other by their position or by some other relation ("Manager", "President", "Teacher", "X's grandmother", etc) but it's still awkward here, especially considering that Mel calls Stella "Stella-san". Obviously I can't have Marie calling her "Mel's Master" to her face in English since I don't walk up to Bob's mom and say "Hey, Bob's mom, how are you?"
I think the way people refer to each other is one of the most consistently awkward parts of translating. At least this isn't as bad as in Happy Sugar Life, where it wasn't until chapter 21 that someone finally referred to Asahi by some gendered language. I assumed he was a boy from the beginning, but nobody ever used "he" or "him" or "son" or "brother", so I was anxious that it'd suddenly be revealed that he was actually a she and had been from the beginning.... This kind of thing happens a lot when characters discuss people. In English you have to use a gendered pronoun, since people almost always say "he" or "she" when discussing someone if they know their gender (I know usage of "they" is possible, but when discussing a known person, it's restricted to the very rare cases in which that person doesn't identify as male or female—this situation is basically nonexistent in manga). When translating sometimes you just have to guess the gender and pray that the person isn't introduced later in a way that proves you wrong.
I salute all Japanese translators lol. Thank you for the info though, all these were quite interesting. As someone said in a previous comment, Itou must have made a bet with her editor that she would pulled out the whole series without giving master a name lol. At least we know she's a woman though.