The Butterfry (Madame's) family was cursed by a spirit demon, the one that appears in this chapter, due to a woman in her family in the past refusing to give up her mundane husband to marry the shota spirit that had became obsessed with her beauty. Thus, all men and women of the direct family line would become morbidly obese, inversely proportional to their original beauty (basically, the prettier they were supposed to be, the fatter and uglier they'd be under the curse).
The Hot Springs Resort MC made in the village was originally just a game location in the "Great Empire" that provided some health benefits to players who stayed there (like how in some games, resting/relaxing grants a temporary minor bonus plus full health recovery and debuff removal). The Madame also took up yoga classes while regularly visiting the resort, and the combination of the healing effects/debuff removal plus light exercise made her overpower the curse. Basically, she was regaining her original beauty and vitality faster than the curse could keep up, thanks to the passive effects of the facility, and eventually, the curse broke down, and now her health regimen was accelerated and turned her into a hot momma due to no longer having the curse active. Which pissed the shota.
