Actually Sammael. The angel who wrestled with Jacob, who refused to give his name since Jacob might use it against him, is believed by Jewish commentators to be Sammale, the terrible angel of death and poison, whose name means Venom of God. (biblical reference are Revelation 19:12; Uudges 13:18; Genesis 32:29.) By the 13th century, Cabbalists had invented an evil sephiroth to match the ten divine sephiroth. They are ruled by arch-demons under the command of Sammael, the fell angel of poison.

("The Horror at Red Hook")