I have no idea why the main protagonist's name was translated to Yohannna and Yohanna, not even staying consistent with your own translation. Pretty much everywhere else tranlates it to Yohan. If you want to keep the original Korean honorifics, that's fine, but the current translation is just confusing.
This is why I suggested reading the official novel translation. Aside from a very few grammatical and spelling errors, it was pretty good. I know I would reference it if I was trying to translate it and was struggling with it.