Before I start, I will preface this by mentioning that I am looking at both one of the fan translations as well as the official English translation because I am pretty well aware as someone that's bilingual that with translation, there can multiple ways to translate a phrase (or longer). As I've seen some people start describing it recently, it is both interpreting as much as it is translating. For reference, I am a native speaker of both English and Russian.
I’m primarily going to be looking at how Gogol describes his relationship with Fyodor (well how he sees it from his end to be specific), but will be showing the prior page for more context of the conversation. Spoilers for Ch 78, p 29-30 (vol 18).
Context
^fan translation^
I don’t have scans of the official version but the key differences that I’ll be looking at are Gogol saying (fan → official translation):
“Yet” “Dos-kun was different” → “...Except...” “...for Dostoy.”
“Dos-kun was the one person in my life who understood. My intimate friend. That’s what I thought.” → “Dostoy’s my only friend...the only one who gets me. That’s what I thought.”
Analysis
Gogol describes Fyodor as “my intimate friend” in the fan translation and “my only friend” in the official translation → I don’t know that much about levels of friendship in Japanese and how those translate to nicknames and naming diminutives being used, but fun fact about Russian (coming from a Russian): although the literal translation for "friend" is друг, it’s actually closer to the Russian equivalent of "close friend" or "best friend" with how it is used. Hence why (at least from my experience) the literal translation for “best friend” isn’t really used among Russians.
Also, although Gogol calls Dostoyevsky “Dos-kun” in the fan translations (and the original Japanese version too) and “Dostoy” in the Yen Press translation (vol 18), the actual Russian equivalent/usage of this would most likely be Fedya, considering them being close friends and basically using nicknames. The more appropriate terminology for this would actually be (naming) diminutive (you learn something new every day lol).
I'm not necessarily calling any of the official versions (Japanese or English) wrong, but I guess I'm pretty much calling them a little bit inaccurate from the perspective of a native Russian speaker. Since we can already see Gogol calling Fyodor by what is comparably a very similar nicknaming convention to what he'd be using in Russian (as the two of them are that after all), to me it just makes more sense for Gogol to use Fedya instead, especially given how he describes their closeness from his own point of view on the relationship. Gogol calling Fyodor "my intimate friend" in the fan translation and "my only friend" in the official one to be specific. In fact, Gogol could’ve almost equally likely referred to Fyodor by his middle name, Mikhailovich, or a diminutive of that instead. We’ve seen characters refer to each other by their real names and not their pen names a couple of times already (Elise calling Mori “Rintaro” and Fukuzawa calling Fukuchi “Genichiro”), so it wouldn’t be too strange to see middle names being used as well.
Whether someone is referred to by their first or last name in Russian is very much comparable to English. Last names are more so for formalities and showing respect (ie. professors and teachers, historical figures, etc). Close friends are typically on a first-name basis, sometimes nicknames (ie. a shortening of their first name).
Sources:
Ch 78 raws: @akutagawaprize (full ver.)
Ch 78 fan translation referenced: @akai-koutei (full ver.)
Ch 78 official translation: Yen Press (thank you Leigh for providing me with this as I don't have a copy of vol 18 yet)
Also thank you @chazukekani for helping to confirm what the Japanese text said (in Japanese)
Additional source when you can see a description of different ways to describe levels of friendship among Russians
More in-depth info and a list of some Russian name diminutives
i made a new bsd chapter bingo a while back but never posted it. so anyway here’s chapter 78. these are all only applicable to the decay of angels arc but still let me know if i should revisit another chapter and check stuff off ;)
also yes theres a row entirely dedicated to characters we haven’t seen in like a year. two have miraculously returned..... but the other three are still gone 😔
I bet the yandere-scenario blogs are gonna have a field day with Nikolai now... All I can do is sit back and wait for the chaos to unfold. (Though really, of all the ways it could have gone, I’m still shocked that Asagiri both made Nikolai into a yandere and did it in a way true to his character like damn)