
Cassiel, seemingly in control of thunder, along with nine sigils associated with the demon. Engraving from Schieble's Faustbuch.

The demon Cassiel, ruler of the Day of Saturn, with his sigils, two derived from the magic square of Saturn. From Barrett's "The Magus" of 1801.
Cassiel (Hebrew: קפציאל = Qaftsi'El "God is my leap") is listed as one of the eleven Servitors of Rahab. His rank is given as chief.
In mythology[]

Qafsiel amulet from the 15th century
In Jewish mysticism and Mesopotamian mythology, Cassiel is associated with the planet Saturn and the direction north. He is the controller of the moon.
In the magical text Berit Menuchah, Cassiel is associated with Kefitzat Haderech, the ability to travel quickly through space. Magic spells using his name are cast to create destruction, to scatter crowds, to cause a person to wander aimlessly, or to fall from a position of power.
Ancient Hebrew amulets bearing his name are used to drive away one's enemies. The words on the charm are written with the blood of a bird and then tied to the foot of a dove. The dove is then set to flight, taking one's enemy with it. Should the bird refuse to fly, it is a sign that one's enemies won't depart either.
Quotes[]
"the nature of them (spirits of Saturday) is to sow discords, hatred, evil thoughts and cogitations, to give leave to kill and murder, and to lame or maim every member."
"Those spirits who appear in a kingly form, have a much higher dignity than them who take an inferior shape; and those who appear in a human shape, exceed in authority and power them that come as animals; and again, these latter surpass in dignity them who appear as trees or instruments, and the like: so that you are to judge of the power, government, and authority of spirits by their assuming a more noble and dignified apparition." Francis Barrett