blood-thirsty

— […] Diodorus also relates of Caligula, predecessor to Nero, that his nurse used to moisten the nipples of her breast frequently with blood to make Caligula take the better hold of them; which, says Diodorus, was the cause that made him so blood-thirsty and cruel all his life-time after, that he not only committed frequent murder by his own hand, but likewise wished that all human kind wore but one neck that he might have the pleasure to cut it off.