Thanks for the chapter!
Ok, so she's a Demon Queen equivalent in age to a 15 year old human. Guess that explains why barely has half the HP of the lowest party member yet almost double MP of the highest member (not counting hero who's OP,) although the members seems rather low level for a hero party. Would at least expect their values to be in the mid to upper hundreds. In any case, I bet the hero hasn't reported back yet and the knights in the first chapter are likely the king's troops sent for her after the rest of the hero party reported back once they finally walked back home.