Are you talking about the dialogue? To make it, I used the Dialogizer Module. Basically, the way it works is that it can either pull text directly from the script in the widgets or card scripts (in which case the font can't be changed) or from a custom text field. I think it should be possible to change each event so that it pulls the text from a field rather than the script using field.value so that it retains the font formatting with a custom Cyrillic font.
(I hope I understood your question correctly lol)
