"According to tradition, Samael is the king of all demons, the angel of death, the husband of the demonic Lilith, and the archenemy of Michael the archangel and of Israel. He is associated with Mars, the left side, the north, and Tuesday. His name is not to be spoken aloud in case doing so draws his attention, and thus he is referred to colloquially by vocalizing only the first two letters of his name."
https://www.britannica.com/topic/Samael
"Samael, from the amoraic period onward the major name of Satan in Judaism. The name first appears in the account of the theory of angels in the Ethiopic Book of Enoch 6, which includes the name, although not in the most important place, in the list of the leaders of the angels who rebelled against God."
https://www.jewishvirtuallibrary.org/samael
"SAMAEL’S SIN
Because of the reality of the authorities, inspired by the spirit of the father of truth, the great messenger referring to the authorities of the darkness told us that “our contest is not against flesh and blood, rather, the authorities of the universe and the spirits of wickedness.” I have sent you this because you inquire about the reality of the authorities.
Their chief is blind. Because of his power and his ignorance and his arrogance he said, with his power, “I am god; there is no other but me.”
When he said this, he sinned against all. This speech rose up to incorruptibility. Then there was a voice that came forth from incorruptibility, saying, **“You are wrong, Samael,”** that is, god of the blind.
His thoughts became blind. And having expelled his power—that is, the blasphemy he had spoken—he pursued it down to chaos and the abyss, his mother, at the instigation of Pistis Sophia. She established each of his offspring in conformity with its power, after the pattern of the realms that are above, for by starting from the invisible world the visible world was invented.
As incorruptibility looked down into the region of the waters, her image appeared in the waters, and the authorities of the darkness became enamored of her. But they could not lay hold of that image which had appeared to them in the waters, because of their weakness, since beings that merely have soul cannot lay hold of those that have spirit. For they were from below, while it was from above."
http://www.gnosis.org/naghamm/Hypostas-Barnstone.html
"Then when Pistis saw the impiety of the chief ruler, she was filled with anger. She was invisible. She said, "You are mistaken, Samael," (that is, "blind god"). "There is an immortal man of light who has been in existence before you, and who will appear among your modelled forms; he will trample you to scorn, just as potter's clay is pounded. And you will descend to your mother, the abyss, along with those that belong to you. For at the consummation of your (pl.) works, the entire defect that has become visible out of the truth will be abolished, and it will cease to be, and will be like what has never been." Saying this, Pistis revealed her likeness of her greatness in the waters. And so doing, she withdrew up to her light."
http://www.gnosis.org/naghamm/origin.html
"In the Jewish literature of the rabbis, Satan is portrayed as a singular being who lures men into sin, and as prosecutor in the divine tribunal, trying to convince God to mete out harsh penalties. He is said to been a powerful angel, able to fly and assume the shape of men, women and animals.
This devil was often called Ashmedai or Asmodeus, a name deriving from a Zoroastrian evil demon, or Samael, a demonic entity also mentioned in the gnostic literature found in Nag Hammadi (a collection of early Christian and gnostic texts discovered near the Egyptian town of the same name in 1945.) In the Talmud he is conflated with the Angel of Death and the Evil Inclination"
https://www.haaretz.com/archaeology/2018-10-23/ty-article-magazine/.premium/do-jews-believe-in-the-devil/0000017f-e295-d75c-a7ff-fe9ddb3b0000
"This gloomy ruler has three names: the first name is Yaldabaoth, the second is Sakla, the third is Samael."
http://www.gnosis.org/naghamm/apocjn-meyer.html