The two Rhinocentaurs had been living a decent enough life, but they were having an early life crisis at the same time. They were effectively prisoners in the Midnight Inn, not that they went around telling people that. There was no point in antagonizing his jailers.
But living in this prison had over the years not only advanced their cultivation, but also improved their cultivation talent.
They were much stronger now than they were before, healthier than before, and had greater chances of raising their cultivation level to a higher ceiling. The most absurd thing was that they didn't have to do anything special to achieve this - they merely had to live in the Inn for it.
The magical energy within the Midnight realm nourished their cultivation, the fresh air and clean food nourished their bodies, and the generally peaceful and relaxing environment nourished their souls. For all intents and purposes, they were in heaven.
