In the biblical Apocrypha, in the books of Enoch and Jubilees, the Grigori were the group of fallen angels who mated with mortal women (Genesis 6:2).
The leader was Samyaza. They brought with them knowledge to pass on to the mortals.
*Armaros taught the resolving of enchantments
* Araqiel taught signs of the earth
* Azazel - how to make weapons, ornaments and cosmetics
* Baraqel - astrology
* Chazaqiel - meterology
* Kokabiel - secrets of wisdom
*Sariel - cosmology (moon)
* Shamsiel - signs of the sun
* Tamiel - science of abortion

The Nephilim (Hebrew) were the "men of renown", "mighty men", giants and Titans that were created by "the sons of god and the daughters of men".