Semjaza

6:1) And it came to pass when the children of men had multiplied that in those days were born unto them beautiful and comely daughters.
6:2) And the angels, the children of the heaven, saw and lusted after them, and said to one another: 'Come, let us choose us wives from among the children of men
6:3) and beget us children.' And Semjaza, who was their leader, said unto them: 'I fear ye will not indeed agree to do this deed,
6:4) and I alone shall have to pay the penalty of a great sin.'
6:5) And they all answered him and said: 'Let us all swear an oath, and all bind ourselves by mutual imprecations 5 not to abandon this plan but to do this thing.' Then sware they all together and bound themselves by mutual imprecations upon it.
8:3) Semjaza taught enchantments, and root-cuttings, 'Armaros the resolving of enchantments, Baraqijal (taught) astrology, Kokabel the constellations, Ezeqeel the knowledge of the clouds, Araqiel the signs of the earth, Shamsiel the signs of the sun, and Sariel the course of the moon. And as men perished, they cried, and their cry went up to heaven.
9:7) And Semjaza, to whom Thou hast given authority to bear rule over his associates.
9:8) And they have gone to the daughters of men upon the earth, and have slept with the women, and have defiled themselves, and revealed to them all kinds of sins.
9:9) And the women have borne giants, and the whole earth has thereby been filled with blood and unrighteousness.
10:9) And to Gabriel said the Lord: 'Proceed against the bastards and the reprobates, and against the children of fornication: and destroy [the children of fornication and] the children of the Watchers from amongst men [and cause them to go forth]: send them one against the other that they may destroy each other in battle: for length of days shall they not have.
10:10) And no request that they (i.e. their fathers) make of thee shall be granted unto their fathers on their behalf; for they hope to live an eternal life, and that each one of them will live five hundred years.'
10:11) And the Lord said unto Michael: 'Go, bind Semjaza and his associates who have united themselves with women so as to have defiled themselves with them in all their uncleanness.
10:12) And when their sons have slain one another, and they have seen the destruction of their beloved ones, bind them fast for seventy generations in the valleys of the earth, till the day of their judgement and of their consummation, till the judgement that is for ever and ever is consummated.
10:13) In those days they shall be led off to the abyss of fire: and to the torment and the prison in which they shall be confined for ever.
10:14) And whosoever shall be condemned and destroyed will from thenceforth be bound together with them to the end of all generations.
10:15) And destroy all the spirits of the reprobate and the children of the Watchers, because they have wronged mankind.

Notes

While Azazel seems easy to connect with the Israeli traditions associated with Yom Kippur, Semjaza, as a figure seems to be unconnected to any other tradition.

Cross-References