Bloodthirstiness… The desire to kill someone… These strange—though for some obvious—ideas have always pursued people. And even if you deprive them of all technologies, opportunities, and knowledge, they will still look for a chance to kill and maim. At best, to injure. But they will never give up the possibility of spilling someone else’s blood. After all, even knowledge of the many bloody wars in the past has never stopped them. It’s as if memory of such horrors simply gets erased… Someone powerful and extremely cruel is conducting a terrifying experiment on Humankind.