Any normal Cultivation Skill would strengthen the body and prolong life.
Unless one had a severe or strange illness, or was poisoned or injured, they should never be as sallow and skinny as Wang Xingjian.
But despite his obviously unhealthy appearance, Wang Xingjian's spirit and demeanor were unusually vibrant. He didn't seem injured or poisoned at all.
He had to be practicing an Evil Skill.
In truth, as long as the Evil Skill didn't involve heinous acts during its cultivation or drive its user insane, practicing one wasn't that rare, at least not within these gangs.
It wasn't like joining a martial arts academy or a Sect, where one first had to find a master who would then transmit their skills.
In such places, if a master discovered their disciple was secretly practicing an Evil Skill, expulsion would be considered a light punishment.
A more hot-tempered master might kill you with a single palm strike, letting you start over in the next life.
