@mimisan
I've also read all chapters that were available as of when I released 9.2, and I've made my choices based on them.
Basically they are special
Exactly my point. I never claimed they were different creatures, but I did say "the words are used like they are".
And no, Kazuto's family is not referred
only as "hero's clan". Any black-haired person is "a yuusha", not just Kazuto nor just for people doing heroic deeds.
That is enough to consider "yuusha" to be "like a different species". Therefore, it's necessary to use a word that does not imply "being heroic", as even Sakurako is called yuusha despite her family not officially recognizing her as such, nor is she famous for doing something at all, let alone something a hero would do.
"Brave" is the closest I can find, regardless of the "feeling" of the translation.
Maybe Kazuto should've been called "hero Kazuto", but that's the only place where "hero" would work correctly.
For demons it works better though: a demon without horns is not a demonlord, so here it's actually plausible to consider being a demonlord an actual different category.
Darkneria (check the official covers, this is the real spelling of her name) is not a normal demon due to her horns, so using "king of the demons" (i.e. "demon king"), would not really show this difference as using "demonlord" (without a space in the middle) does, in my opinion.
On the other hand, maou so far has been used only for the demon king, but at the same time, the usage of yuusha and the horns being a characteristic of the maou's family, means that being a maou is also being special and different, thus I concluded that it was necessary to consider that role of demon king/demonlord the same way as I did with yuusha.