Revived

No, the plot isn't really tied to Nicholas.
I think I need to strengthen the monk hero (increase his spellcasting skill so that he can deal more damage with Holy Word), since he's being killed so quickly.

But it will be difficult with just one hero. An orange hero will come and attack the castle, then more demons and an archpriest will arrive. So I advise you to also level up Kolya in parallel, for example, by fighting hydras in the temple.