Hush Hush, Sandman Slim, City of Bones ....
If you really think about it, it's all the same isn't it? I never heard of the "Nephilim" until a few years ago, but I can certainly understand the allure. Superhuman powers, immortality, beauty, purity, sexuality, and an endless supply of historical mythology tied in controversy. Mentioned in the Hebrew Bible in Genesis and Numbers, the Nephilim are the offspring of Angels and Humans; perfectly shrouded in a comfortable amount of mystery for artistic license.
Sound familiar? Hercules, Theseus, Perseus; the half god bastards commonly celebrated in Greek mythology for their miraculous feats may ring a bell.
I guess it's all about the spin. Recycle, renew, refresh.