Bloodthirstiness… The desire to kill someone… These strange—at least to some—concepts have always haunted people. And even if you strip them of all technologies, opportunities, and knowledge, they will still look for a way to kill and maim. At best, to injure. But they will never give up the chance to spill someone else’s blood. Because even knowledge of countless bloody wars in the past never stops them. It’s as if the memory of such horrors simply gets erased… Someone powerful and very cruel. Someone who conducts a terrible experiment on Humankind.