Techniques of body refinement relied on the vitality within the blood to speed up the process of healing and strengthening. By forcing your blood along certain paths, it would be similar to completing an array within your body that can siphon this vitality away for your benefit.
It seemed that not only were the meridian pathways hidden magic circles, but blood veins were similar in the fashion as well. In reality, Dyon knew this already. After all, what was Runic Vein theory if not a practice that took advantage of this truth?
In addition, there were blood manipulation techniques that followed this same path as well. Dyon had learned many such techniques due to him following his Master's teachings.
Dyon rarely used these blood manipulation techniques, but that wasn't because they were useless. Rather, they stemmed from mere common grade techniques, so not all of them ended up as powerful as his [Vanishing Fists].