Cultivation, basically. With a few Avatar bending elements tossed in. I wonder if this energy just a quirk of their biology or if it has some link to the planet? Like, is there something unique about their planet that lets it put out a special energy that the natives can absorb and harness for power? If they are taken to another world would they still be able to gather this "fasha" energy?
the Fasha energy is a quirk of their biology, mainly due to the form of energy already being on the planet before, if they were to go to a different planet, their rate of growth would dramatically slow down due to the lack of Fasha energy in the atmosphere on any other planet, but they would still be able to get stronger at an incredible rate if any magic or ki energy is on a planet they are on, since Fasha is both ki and magic, it can be replenished by eating and resting normally.
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