☆ An action called the “forbidden violation” in Shangri-la. Just as the interbreeding of humans and youkai is considered “taboo”, there are misgivings that the mixing of unlike things will disrupt the balance, and so it was made taboo. At this point in time there is already a large gap between the human race and the youkai race.
☆ It is believed by the Sanbutsushin that this act of combining science and dark magic is what is the cause for what is known as the Minus Wave that is making the demon population become feral and attacking humans. This may or may not be the case as Gyokumen Koushu and Dr. Ni have hinted that it is part of their plan and not just a side-effect of their experiments to revive Gyumaoh.