An Astral Slayer is a greater Demon of immense power. Warding off such a being takes many enchantments and the method is a protracted affair. A surprise attack by an Astral Slayer is therefore almost always successful. Few have summoned such beings and lived, for they are powerful and hard to control. Shanzikuul was the last to be known to have done so, when he sent such a being to kill the foremost Great Wizard of an Old World fellowship of wizards who had been guarding a Staff of Rulership.