Despite being a Warlock, Yun Qi never allowed Shen Yanxiao to perform any bloody curse techniques.
Yun Qi once said that there were a lot of dangers and temptations in the path of a Warlock. Those powerful curse techniques would also bring huge backlash to the caster. While gaining powerful strength, the soul would also fall into the abyss at the same time and be enveloped by evil from then on.
Forbidden techniques were called forbidden because their existence violated the force of nature and because most of the mediums needed for these curse techniques were parts of the dead or the living.
In a sense, forbidden techniques tended to do things like extracting other people's souls, doing things that defied the natural order and changed people's lives.
Shen Yanxiao had never seen what the process of a real forbidden technique was like, but the two things that Qing Jun used today made her deeply realize that the things Yun Qi told her were true.