The blood eagle was reportedly first thought up by Ivarr the Boneless, one of the most notorious and heinous Vikings of the 9th century, who used it to strike fear into his enemies. So what did it actually involve? According to Smithsonian Magazine:
First the intended victim would be restrained, face down; next, the shape of an eagle with outstretched wings would be cut into his back. After that, his ribs would be hacked from his spine with an ax, one by one, and the bones and skin on both sides pulled outward to create a pair of “wings” from the man’s back. The victim, it is said, would still be alive at this point to experience the agony of what Turner terms “saline stimulant”—having salt rubbed, quite literally, into his vast wound. After that, his exposed lungs would be pulled out of his body and spread over his “wings,” offering witnesses the sight of a final bird-like “fluttering” as he died.By some accounts, seeing the Christian art representation of angels might have given them the idea.
Unlike the Nazis, who tried destroying evidence of the Holocaust at the end of the war because they knew they were doing wrong, ISIS publicizes its torture of people; much like the Vikings. Alfred turned them back. Does Europe still have such men?