Passive Ability—Energy Sink!
Feifei absorbed the miasma into her body, turning it into two streams. One was used to strengthen her body while the other flowed into her stomach, becoming absorbed by the stomach walls.
Energy Sink was her favorite passive ability in that it converted any forms of energy and stored them all in a mini world that was in her stomach. As she had obtained this passive ability from Layer 3, the energy in the mini world took the form of the healing water from Layer 3.
Energy Sink was basically a reservoir of energy she could store in herself and use upon necessary. Plus, since it was tied to her stomach, as her body density grew, it meant that her stomach walls grew similarly.
So, the quantity and quality of energy she could store in her Energy Sink continued to increase. Moreover, as it was stored as the healing water, Feifei never had to be worried about being able to heal from her wounds.