Kingdom Come: Deliverance has sold more than one million copies in less than a month. Its all-time concurrent player peak is higher than The Witcher 3's. So why is a janky role-playing game set in the Holy Roman Empire so popular?

TBH this almost strikes me as answering it's own question, as this thing alone is distinguished enough to win attention from me. Basically only other thing that would make me explode with excitement would be a movie or game (action or rpg) with centered on the varangian guard, because I'm the kind of person who always plays with Byzantium if available. Actually a game set in Warring States or Three Kingdoms period of China would be plenty cool too, but also make it mythological and magical.