原The proper transcription for the spelling provided in this entry (Севастьян) is actually Sevastyan, not Sevastian. You see, the standard transcription for the letter я in the name is "ya", while "ia" and "ja" are usually considered variant transcriptions. As such, one can argue that for this particular spelling, Sevastyan is the main Russian form and Sevastian is the variant transcription.
For more information about this, please see the comment that I left at the entry for Sevastyan (in the main database), which is quite a bit longer and thus more useful.
http://kurufin.ru/html/Rus_nam
译 在这个条目（Севастьян）提供的拼写正确的转录实际上是Sevastyan，而不是塞瓦斯蒂安。你看，姓名中的字母я的标准转录是“ya”，而“ia”和“ja”通常被认为是变体转录。因此，人们可以认为，对于这种特定的拼写，Sevastyan是主要的俄语形式，Sevastian是变种转录。有关这方面的更多信息，请参阅我在Sevastyan的条目（在主数据库中）留下的评论，这是相当长一点，因此更有用.- http://kurufin.ru/html/Rus_names/rus_s.html（俄语;向下滚动，直到你看到“Sebastianus”在右边的一列） - http ：//kurufin.ru/html/Translate/sevastyan.html（俄文） - https://ru.wikipedia.org/wiki/%D0%A1%D0%B5%D0%B2%D0%B0%D1% 81％D1％82％D1％8C％D1％8F％D0％BD（俄语）。
For more information about this, please see the comment that I left at the entry for Sevastyan (in the main database), which is quite a bit longer and thus more useful.
- http://kurufin.ru/html/Rus_names/rus_s.html (in Russian; scroll down until you see "Sebastianus" in one of the columns on the right)
- http://kurufin.ru/html/Translate/sevastyan.html (in Russian)
- https://ru.wikipedia.org/wiki/%D0%A1%D0%B5%D0%B2%D0%B0%D1%81%D1%82%D1%8C%D1%8F%D0%BD (in Russian).