What is ระบบศักดินา?

Not exactly. ‘Medieval’ refers to a historical era, while a feudal system is a particular social and economic arrangement common in many medieval societies. You can have medieval settings without strict feudal structures, and you can use feudal-like hierarchies in non-medieval or fantasy worlds.

You don’t need perfect accuracy for a compelling story, but plausibility and internal consistency matter. Small authentic details (inheritance rules, a lord’s court, a tenant’s duties) help readers suspend disbelief—avoid glaring anachronisms unless your world intentionally mixes eras.

Center characters’ agency and consent: show negotiation, consequences, and emotional complexity. Use power imbalance to create tension and character growth rather than to excuse coercion. Give the lower-status character meaningful choices and consequences for those choices.

Yes. Keep the core mechanics—land/privilege exchanged for service, legal/ceremonial obligations, and restricted mobility—but swap specifics (land for control of trade routes, knights for mercenary companies) or layer magic, different laws, or cultural norms to make the system feel fresh.