At The Same Time

Blood Aura was nothing more than just Qi. It was Qi that had transformed inside a human or beast's body and embedded itself into one's blood thanks to the Blood Essence.

Blood Aura could not be freely converted into Qi, but it was possible if one used some techniques that allowed for it. This usually applied to blood aura outside of one's body, but there were secret techniques or forbidden ones that allowed for the blood aura in one's own body to be changed into Qi.

However, that was something very rare and only a handful of techniques existed that made it possible for someone to use it like that.

Conversely, no techniques existed that could turn Qi into a blood aura. It took time for the Qi in one's body or the surroundings to be absorbed by the Blood Essence to turn into blood aura.